The pstore RAM backend can get called during resume, and must be defensive
against a suspended time source. Expose getnstimeofday logic that returns
an error instead of a WARN. This can be detected and the timestamp can
be zeroed out.
Reported-by: Doug Anderson <dianders@chromium.org>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Conflicts:
Documentation/networking/ip-sysctl.txt
drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
Both conflicts were simply overlapping context.
A build fix for qlcnic is in here too, simply removing the added
devinit annotations which no longer exist.
Signed-off-by: David S. Miller <davem@davemloft.net>
proc_cpuset_show() has a spurious -EINVAL assignment which does
nothing. Remove it.
This patch doesn't make any functional difference.
tj: Rewrote patch description.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
to tracing_on" caused two regressions.
1) The irqs off latency tracer no longer starts if tracing_on is off
when the tracer is set, and then tracing_on is enabled. The tracing_on
file needs the hook that tracing_enabled had to enable tracers if they
request it (call the tracer's start() method).
2) That commit had a separate change that really should have been a
separate patch, but it must have been added accidently with the -a
option of git commit. But as the change is still related to the commit
it wasn't noticed in review. That change, changed the way blocking is
done by the trace_pipe file with respect to the tracing_on settings.
I've been told that this change breaks current userspace, and this
specific change is being reverted.
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Merge tag 'trace-3.8-rc3-regression-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing regression fixes from Steven Rostedt:
"The clean up patch commit 0fb9656d95 "tracing: Make tracing_enabled
be equal to tracing_on" caused two regressions.
1) The irqs off latency tracer no longer starts if tracing_on is off
when the tracer is set, and then tracing_on is enabled. The
tracing_on file needs the hook that tracing_enabled had to enable
tracers if they request it (call the tracer's start() method).
2) That commit had a separate change that really should have been a
separate patch, but it must have been added accidently with the -a
option of git commit. But as the change is still related to the
commit it wasn't noticed in review. That change, changed the way
blocking is done by the trace_pipe file with respect to the
tracing_on settings. I've been told that this change breaks
current userspace, and this specific change is being reverted."
* tag 'trace-3.8-rc3-regression-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix regression of trace_pipe
tracing: Fix regression with irqsoff tracer and tracing_on file
Nothing's protected by RCU in rebind_subsystems(), and I can't think
of a reason why it is needed.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
These 2 syncronize_rcu()s make attaching a task to a cgroup
quite slow, and it can't be ignored in some situations.
A real case from Colin Cross: Android uses cgroups heavily to
manage thread priorities, putting threads in a background group
with reduced cpu.shares when they are not visible to the user,
and in a foreground group when they are. Some RPCs from foreground
threads to background threads will temporarily move the background
thread into the foreground group for the duration of the RPC.
This results in many calls to cgroup_attach_task.
In cgroup_attach_task() it's task->cgroups that is protected by RCU,
and put_css_set() calls kfree_rcu() to free it.
If we remove this synchronize_rcu(), there can be threads in RCU-read
sections accessing their old cgroup via current->cgroups with
concurrent rmdir operation, but this is safe.
# time for ((i=0; i<50; i++)) { echo $$ > /mnt/sub/tasks; echo $$ > /mnt/tasks; }
real 0m2.524s
user 0m0.008s
sys 0m0.004s
With this patch:
real 0m0.004s
user 0m0.004s
sys 0m0.000s
tj: These synchronize_rcu()s are utterly confused. synchornize_rcu()
necessarily has to come between two operations to guarantee that
the changes made by the former operation are visible to all rcu
readers before proceeding to the latter operation. Here,
synchornize_rcu() are at the end of attach operations with nothing
beyond it. Its only effect would be delaying completion of
write(2) to sysfs tasks/procs files until all rcu readers see the
change, which doesn't mean anything.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Colin Cross <ccross@google.com>
Clockevent cleanup series from Shawn Guo.
Resolved move/change conflict in mach-pxa/time.c due to the sys_timer
cleanup.
* clocksource/cleanup:
clocksource: use clockevents_config_and_register() where possible
ARM: use clockevents_config_and_register() where possible
clockevents: export clockevents_config_and_register for module use
+ sync to Linux 3.8-rc3
Signed-off-by: Olof Johansson <olof@lixom.net>
Conflicts:
arch/arm/mach-pxa/time.c
Commit 0fb9656d "tracing: Make tracing_enabled be equal to tracing_on"
changes the behaviour of trace_pipe, ie. it makes trace_pipe return if
we've read something and tracing is enabled, and this means that we have
to 'cat trace_pipe' again and again while running tests.
IMO the right way is if tracing is enabled, we always block and wait for
ring buffer, or we may lose what we want since ring buffer's size is limited.
Link: http://lkml.kernel.org/r/1358132051-5410-1-git-send-email-bo.li.liu@oracle.com
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
clockevents_config_and_register is a handy helper for clockevent
drivers, some of which might support module build, so export the symbol.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Olof Johansson <olof@lixom.net>
bio_{front|back}_merge tracepoints report a bio merging into an
existing request but didn't specify which request the bio is being
merged into. Add @req to it. This makes it impossible to share the
event template with block_bio_queue - split it out.
@req isn't used or exported to userland at this point and there is no
userland visible behavior change. Later changes will make use of the
extra parameter.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
bio completion didn't kick block_bio_complete TP. Only dm was
explicitly triggering the TP on IO completion. This makes
block_bio_complete TP useless for tracers which want to know about
bios, and all other bio based drivers skip generating blktrace
completion events.
This patch makes all bio completions via bio_endio() generate
block_bio_complete TP.
* Explicit trace_block_bio_complete() invocation removed from dm and
the trace point is unexported.
* @rq dropped from trace_block_bio_complete(). bios may fly around
w/o queue associated. Verifying and accessing the assocaited queue
belongs to TP probes.
* blktrace now gets both request and bio completions. Make it ignore
bio completions if request completion path is happening.
This makes all bio based drivers generate blktrace completion events
properly and makes the block_bio_complete TP actually useful.
v2: With this change, block_bio_complete TP could be invoked on sg
commands which have bio's with %NULL bi_bdev. Update TP
assignment code to check whether bio->bi_bdev is %NULL before
dereferencing.
Signed-off-by: Tejun Heo <tj@kernel.org>
Original-patch-by: Namhyung Kim <namhyung@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Prarit's excellent bug report:
> In recent Fedora releases (F17 & F18) some users have reported seeing
> messages similar to
>
> [ 15.478160] kvm: Could not allocate 304 bytes percpu data
> [ 15.478174] PERCPU: allocation failed, size=304 align=32, alloc from
> reserved chunk failed
>
> during system boot. In some cases, users have also reported seeing this
> message along with a failed load of other modules.
>
> What is happening is systemd is loading an instance of the kvm module for
> each cpu found (see commit e9bda3b). When the module load occurs the kernel
> currently allocates the modules percpu data area prior to checking to see
> if the module is already loaded or is in the process of being loaded. If
> the module is already loaded, or finishes load, the module loading code
> releases the current instance's module's percpu data.
Now we have a new state MODULE_STATE_UNFORMED, we can insert the
module into the list (and thus guarantee its uniqueness) before we
allocate the per-cpu region.
Reported-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Prarit Bhargava <prarit@redhat.com>
You should never look at such a module, so it's excised from all paths
which traverse the modules list.
We add the state at the end, to avoid gratuitous ABI break (ksplice).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
audit_log_start() performs the same jiffies comparison in two places.
If sufficient time has elapsed between the two comparisons, the second
one produces a negative sleep duration:
schedule_timeout: wrong timeout value fffffffffffffff0
Pid: 6606, comm: trinity-child1 Not tainted 3.8.0-rc1+ #43
Call Trace:
schedule_timeout+0x305/0x340
audit_log_start+0x311/0x470
audit_log_exit+0x4b/0xfb0
__audit_syscall_exit+0x25f/0x2c0
sysret_audit+0x17/0x21
Fix it by performing the comparison a single time.
Reported-by: Dave Jones <davej@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's possible for audit_log_start() to return NULL. Handle it in the
various callers.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Julien Tinnes <jln@google.com>
Cc: Will Drewry <wad@google.com>
Cc: Steve Grubb <sgrubb@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The seccomp path was using AUDIT_ANOM_ABEND from when seccomp mode 1
could only kill a process. While we still want to make sure an audit
record is forced on a kill, this should use a separate record type since
seccomp mode 2 introduces other behaviors.
In the case of "handled" behaviors (process wasn't killed), only emit a
record if the process is under inspection. This change also fixes
userspace examination of seccomp audit events, since it was considered
malformed due to missing fields of the AUDIT_ANOM_ABEND event type.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Julien Tinnes <jln@google.com>
Acked-by: Will Drewry <wad@chromium.org>
Acked-by: Steve Grubb <sgrubb@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
down_write_nest_lock() provides a means to annotate locking scenario
where an outer lock is guaranteed to serialize the order nested locks
are being acquired.
This is analogoue to already existing mutex_lock_nest_lock() and
spin_lock_nest_lock().
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 02404baf1b "tracing: Remove deprecated tracing_enabled file"
removed the tracing_enabled file as it never worked properly and
the tracing_on file should be used instead. But the tracing_on file
didn't call into the tracers start/stop routines like the
tracing_enabled file did. This caused trace-cmd to break when it
enabled the irqsoff tracer.
If you just did "echo irqsoff > current_tracer" then it would work
properly. But the tool trace-cmd disables tracing first by writing
"0" into the tracing_on file. Then it writes "irqsoff" into
current_tracer and then writes "1" into tracing_on. Unfortunately,
the above commit changed the irqsoff tracer to check the tracing_on
status instead of the tracing_enabled status. If it's disabled then
it does not start the tracer internals.
The problem is that writing "1" into tracing_on does not call the
tracers "start" routine like writing "1" into tracing_enabled did.
This makes the irqsoff tracer not start when using the trace-cmd
tool, and is a regression for userspace.
Simple fix is to have the tracing_on file call the tracers start()
method when being enabled (and the stop() method when disabled).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
In various network workloads, __do_softirq() latencies can be up
to 20 ms if HZ=1000, and 200 ms if HZ=100.
This is because we iterate 10 times in the softirq dispatcher,
and some actions can consume a lot of cycles.
This patch changes the fallback to ksoftirqd condition to :
- A time limit of 2 ms.
- need_resched() being set on current task
When one of this condition is met, we wakeup ksoftirqd for further
softirq processing if we still have pending softirqs.
Using need_resched() as the only condition can trigger RCU stalls,
as we can keep BH disabled for too long.
I ran several benchmarks and got no significant difference in
throughput, but a very significant reduction of latencies (one order
of magnitude) :
In following bench, 200 antagonist "netperf -t TCP_RR" are started in
background, using all available cpus.
Then we start one "netperf -t TCP_RR", bound to the cpu handling the NIC
IRQ (hard+soft)
Before patch :
# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=550110.424
MIN_LATENCY=146858
MAX_LATENCY=997109
P50_LATENCY=305000
P90_LATENCY=550000
P99_LATENCY=710000
MEAN_LATENCY=376989.12
STDDEV_LATENCY=184046.92
After patch :
# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=40545.492
MIN_LATENCY=9834
MAX_LATENCY=78366
P50_LATENCY=33583
P90_LATENCY=59000
P99_LATENCY=69000
MEAN_LATENCY=38364.67
STDDEV_LATENCY=12865.26
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Miller <davem@davemloft.net>
Cc: Tom Herbert <therbert@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix new kernel-doc warning in auditfilter.c:
Warning(kernel/auditfilter.c:1157): Excess function parameter 'uid' description in 'audit_receive_filter'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Paris <eparis@redhat.com>
Cc: linux-audit@redhat.com (subscribers-only)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Switch cgroup to use the new hashtable implementation. No functional changes.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
"tracing: Add trace_options kernel command line parameter"
in consolidating the code, it removed a necessary nul terminator.
This causes writing to the trace_options file to break. Although,
setting the options/<options> file to 1 or 0 still worked fine.
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Merge tag 'trace-3.8-rc2-regression-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing regression fix from Steven Rostedt:
"A change that came in this merge window broke the writing to the
trace_options file. It causes garbage to be read during the compare
of option names, and breaks setting options via the trace_options
file, although options can still be set via the options/<option>
files."
* tag 'trace-3.8-rc2-regression-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix regression of trace_options file setting
The latest change to allow trace options to be set on the command
line also broke the trace_options file.
The zeroing of the last byte of the option name that is echoed into
the trace_option file was removed with the consolidation of some
of the code. The compare between the option and what was written to
the trace_options file fails because the string holding the data
written doesn't terminate with a null character.
A zero needs to be added to the end of the string copied from
user space.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
IA64 defines /proc/sys/kernel/ignore-unaligned-usertrap to control
verbose warnings on unaligned access emulation.
Although the exact mechanics of what to do with sysctl (ignore/shout)
are arch specific, this change enables the sysctl to be usable cross-arch.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit adds event tracing for callback acceleration to allow better
tracking of callbacks through the system.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, callbacks are advanced each time the corresponding CPU
notices a change in its leaf rcu_node structure's ->completed value
(this value counts grace-period completions). This approach has worked
quite well, but with the advent of RCU_FAST_NO_HZ, we cannot count on
a given CPU seeing all the grace-period completions. When a CPU misses
a grace-period completion that occurs while it is in dyntick-idle mode,
this will delay invocation of its callbacks.
In addition, acceleration of callbacks (when RCU realizes that a given
callback need only wait until the end of the next grace period, rather
than having to wait for a partial grace period followed by a full
grace period) must be carried out extremely carefully. Insufficient
acceleration will result in unnecessarily long grace-period latencies,
while excessive acceleration will result in premature callback invocation.
Changes that involve this tradeoff are therefore among the most
nerve-wracking changes to RCU.
This commit therefore explicitly tags groups of callbacks with the
number of the grace period that they are waiting for. This means that
callback-advancement and callback-acceleration functions are idempotent,
so that excessive acceleration will merely waste a few CPU cycles. This
also allows a CPU to take full advantage of any grace periods that have
elapsed while it has been in dyntick-idle mode. It should also enable
simulataneous simplifications to and optimizations of RCU_FAST_NO_HZ.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
It turns out that gcc 4.8 warns on array indexes being out of bounds
unless it can prove otherwise. It gives this warning on some RCU
initialization code. Because this is far from any fastpath, add
an explicit check for array bounds and panic if so. This gives the
compiler enough information to figure out that the array index is never
out of bounds.
However, if a similar false positive occurs on a fastpath, it will
probably be necessary to tell the compiler to keep its array-index
anxieties to itself. ;-)
Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This patch uses the real new value of dynticks_nesting instead of 0 in
rcu_eqs_enter_common().
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Both rcutiny and rcutree define a helper function named
rcu_is_cpu_rrupt_from_idle(), each used exactly once, later in the
same file. This commit therefore declares these helper functions static.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Currently, rcutorture traces every read-side access. This can be
problematic because even a two-minute rcutorture run on a two-CPU system
can generate 28,853,363 reads. Normally, only a failing read is of
interest, so this commit traces adjusts rcutorture's tracing to only
trace failing reads. The resulting event tracing records the time
and the ->completed value captured at the beginning of the RCU read-side
critical section, allowing correlation with other event-tracing messages.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
[ paulmck: Add fix to build problem located by Randy Dunlap based on
diagnosis by Steven Rostedt. ]
The rcutorture tests need to be able to trace the time of the
beginning of an RCU read-side critical section, and thus need access
to trace_clock_local(). This commit therefore adds a the needed
EXPORT_SYMBOL_GPL().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
The as-documented rcu_nocb_poll will fail to enable this feature
for two reasons. (1) there is an extra "s" in the documented
name which is not in the code, and (2) since it uses module_param,
it really is expecting a prefix, akin to "rcutree.fanout_leaf"
and the prefix isn't documented.
However, there are several reasons why we might not want to
simply fix the typo and add the prefix:
1) we'd end up with rcutree.rcu_nocb_poll, and rather probably make
a change to rcutree.nocb_poll
2) if we did #1, then the prefix wouldn't be consistent with the
rcu_nocbs=<cpumap> parameter (i.e. one with, one without prefix)
3) the use of module_param in a header file is less than desired,
since it isn't immediately obvious that it will get processed
via rcutree.c and get the prefix from that (although use of
module_param_named() could clarify that.)
4) the implied export of /sys/module/rcutree/parameters/rcu_nocb_poll
data to userspace via module_param() doesn't really buy us anything,
as it is read-only and we can tell if it is enabled already without
it, since there is a printk at early boot telling us so.
In light of all that, just change it from a module_param() to an
early_setup() call, and worry about adding it to /sys later on if
we decide to allow a dynamic setting of it.
Also change the variable to be tagged as read_mostly, since it
will only ever be fiddled with at most, once at boot.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The wait_event() at the head of the rcu_nocb_kthread() can result in
soft-lockup complaints if the CPU in question does not register RCU
callbacks for an extended period. This commit therefore changes
the wait_event() to a wait_event_interruptible().
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This branch contains a number of cleanups and unifications to various
timer- clock-events- and ARM timer code. The main points are:
1) Convert arch_gettimeoffset to a pointer, so that architectures with
multiple timer implementations can simply set this standard pointer
rather than maintaining their own arch-specific pointers for the
same purpose. Various architectures are converted to using this new
feature.
2) Conversion of ARM timer implementations to use clock_event_devices's
suspend/resume operations, rather than the ARM-specific sys_timer
versions. Thus, the ARM code begins to use more common infra-structure
rather than arch-specific code.
3) Removal of ARM's struct sys_timer completely, now that everything uses
common code.
4) Introduction of drivers/clocksource/clksrc-of.c, which allows ARM clock
source implementations to be moved into drivers/clocksource, with the
need to add SoC-specific header files for each timer initialization
function; instead, all enabled implementations are registered into a
table which a single core function iterates over, and calls the
relevant initialization functions based on device tree. At least the
Tegra and BCM2835 clocksource implementations will use this feature in
the 3.9 kernel cycle.
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Merge tag 'swarren-for-3.9-arm-timer-rework' of git://git.kernel.org/pub/scm/linux/kernel/git/swarren/linux-tegra into next/cleanup
From Stephen Warren:
ARM/...: timer and clock events cleanup, and remove struct sys_timer
This branch contains a number of cleanups and unifications to various
timer- clock-events- and ARM timer code. The main points are:
1) Convert arch_gettimeoffset to a pointer, so that architectures with
multiple timer implementations can simply set this standard pointer
rather than maintaining their own arch-specific pointers for the
same purpose. Various architectures are converted to using this new
feature.
2) Conversion of ARM timer implementations to use clock_event_devices's
suspend/resume operations, rather than the ARM-specific sys_timer
versions. Thus, the ARM code begins to use more common infra-structure
rather than arch-specific code.
3) Removal of ARM's struct sys_timer completely, now that everything uses
common code.
4) Introduction of drivers/clocksource/clksrc-of.c, which allows ARM clock
source implementations to be moved into drivers/clocksource, with the
need to add SoC-specific header files for each timer initialization
function; instead, all enabled implementations are registered into a
table which a single core function iterates over, and calls the
relevant initialization functions based on device tree. At least the
Tegra and BCM2835 clocksource implementations will use this feature in
the 3.9 kernel cycle.
* tag 'swarren-for-3.9-arm-timer-rework' of git://git.kernel.org/pub/scm/linux/kernel/git/swarren/linux-tegra:
clocksource: add common of_clksrc_init() function
ARM: delete struct sys_timer
ARM: remove struct sys_timer suspend and resume fields
ARM: samsung: register syscore_ops for timer resume directly
ARM: ux500: convert timer suspend/resume to clock_event_device
ARM: sa1100: convert timer suspend/resume to clock_event_device
ARM: pxa: convert timer suspend/resume to clock_event_device
ARM: at91: convert timer suspend/resume to clock_event_device
ARM: set arch_gettimeoffset directly
m68k: set arch_gettimeoffset directly
time: convert arch_gettimeoffset to a pointer
cris: move usec/nsec conversion to do_slow_gettimeoffset
Signed-off-by: Olof Johansson <olof@lixom.net>
cgroup already tracks the hierarchy. Follow cgroup->parent to find
the parent and drop cpuset->parent.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Implement cpuset_for_each_descendant_pre() and replace the
cpuset-specific tree walking using cpuset->stack_list with it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Supposedly for historical reasons, cpuset depends on cgroup core for
locking. It depends on cgroup_mutex in cgroup callbacks and grabs
cgroup_mutex from other places where it wants to be synchronized.
This is majorly messy and highly prone to introducing circular locking
dependency especially because cgroup_mutex is supposed to be one of
the outermost locks.
As previous patches already plugged possible races which may happen by
decoupling from cgroup_mutex, replacing cgroup_mutex with cpuset
specific cpuset_mutex is mostly straight-forward. Introduce
cpuset_mutex, replace all occurrences of cgroup_mutex with it, and add
cpuset_mutex locking to places which inherited cgroup_mutex from
cgroup core.
The only complication is from cpuset wanting to initiate task
migration when a cpuset loses all cpus or memory nodes. Task
migration may go through full cgroup and all subsystem locking and
should be initiated without holding any cpuset specific lock; however,
a previous patch already made hotplug handled asynchronously and
moving the task migration part outside other locks is easy.
cpuset_propagate_hotplug_workfn() now invokes
remove_tasks_in_empty_cpuset() without holding any lock.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cpuset is scheduled to be decoupled from cgroup_lock which will make
hotplug handling race with task migration. cpus or mems will be
allowed to go offline between ->can_attach() and ->attach(). If
hotplug takes down all cpus or mems of a cpuset while attach is in
progress, ->attach() may end up putting tasks into an empty cpuset.
This patchset makes ->attach() schedule hotplug propagation if the
cpuset is empty after attaching is complete. This will move the tasks
to the nearest ancestor which can execute and the end result would be
as if hotplug handling happened after the tasks finished attaching.
cpuset_write_resmask() now also flushes cpuset_propagate_hotplug_wq to
wait for propagations scheduled directly by cpuset_attach().
This currently doesn't make any functional difference as everything is
protected by cgroup_mutex but enables decoupling the locking.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cpuset is scheduled to be decoupled from cgroup_lock which will make
configuration updates race with task migration. Any config update
will be allowed to happen between ->can_attach() and ->attach(). If
such config update removes either all cpus or mems, by the time
->attach() is called, the condition verified by ->can_attach(), that
the cpuset is capable of hosting the tasks, is no longer true.
This patch adds cpuset->attach_in_progress which is incremented from
->can_attach() and decremented when the attach operation finishes
either successfully or not. validate_change() treats cpusets w/
non-zero ->attach_in_progress like cpusets w/ tasks and refuses to
remove all cpus or mems from it.
This currently doesn't make any functional difference as everything is
protected by cgroup_mutex but enables decoupling the locking.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cpuset_hotplug_workfn() has been invoking cpuset_propagate_hotplug()
directly to propagate hotplug updates to !root cpusets; however, this
has the following problems.
* cpuset locking is scheduled to be decoupled from cgroup_mutex,
cgroup_mutex will be unexported, and cgroup_attach_task() will do
cgroup locking internally, so propagation can't synchronously move
tasks to a parent cgroup while walking the hierarchy.
* We can't use cgroup generic tree iterator because propagation to
each cpuset may sleep. With propagation done asynchronously, we can
lose the rather ugly cpuset specific iteration.
Convert cpuset_propagate_hotplug() to
cpuset_propagate_hotplug_workfn() and execute it from newly added
cpuset->hotplug_work. The work items are run on an ordered workqueue,
so the propagation order is preserved. cpuset_hotplug_workfn()
schedules all propagations while holding cgroup_mutex and waits for
completion without cgroup_mutex. Each in-flight propagation holds a
reference to the cpuset->css.
This patch doesn't cause any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
In general, we want to make cgroup_mutex one of the outermost locks
and be able to use get_online_cpus() and friends from cgroup methods.
With cpuset hotplug made async, get_online_cpus() can now be nested
inside cgroup_mutex.
Currently, cpuset avoids nesting get_online_cpus() inside cgroup_mutex
by bouncing sched_domain rebuilding to a work item. As such nesting
is allowed now, remove the workqueue bouncing code and always rebuild
sched_domains synchronously. This also nests sched_domains_mutex
inside cgroup_mutex, which is intended and should be okay.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
CPU / memory hotplug path currently grabs cgroup_mutex from hotplug
event notifications. We want to separate cpuset locking from cgroup
core and make cgroup_mutex outer to hotplug synchronization so that,
among other things, mechanisms which depend on get_online_cpus() can
be used from cgroup callbacks. In general, we want to keep
cgroup_mutex the outermost lock to minimize locking interactions among
different controllers.
Convert cpuset_handle_hotplug() to cpuset_hotplug_workfn() and
schedule it from the hotplug notifications. As the function can
already handle multiple mixed events without any input, converting it
to a work function is mostly trivial; however, one complication is
that cpuset_update_active_cpus() needs to update sched domains
synchronously to reflect an offlined cpu to avoid confusing the
scheduler. This is worked around by falling back to the the default
single sched domain synchronously before scheduling the actual hotplug
work. This makes sched domain rebuilt twice per CPU hotplug event but
the operation isn't that heavy and a lot of the second operation would
be noop for systems w/ single sched domain, which is the common case.
This decouples cpuset hotplug handling from the notification callbacks
and there can be an arbitrary delay between the actual event and
updates to cpusets. Scheduler and mm can handle it fine but moving
tasks out of an empty cpuset may race against writes to the cpuset
restoring execution resources which can lead to confusing behavior.
Flush hotplug work item from cpuset_write_resmask() to avoid such
confusions.
v2: Synchronous sched domain rebuilding using the fallback sched
domain added. This fixes various issues caused by confused
scheduler putting tasks on a dead CPU, including the one reported
by Li Zefan.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Reorganize hotplug path to prepare for async hotplug handling.
* Both CPU and memory hotplug handlings are collected into a single
function - cpuset_handle_hotplug(). It doesn't take any argument
but compares the current setttings of top_cpuset against what's
actually available to determine what happened. This function
directly updates top_cpuset. If there are CPUs or memory nodes
which are taken down, cpuset_propagate_hotplug() in invoked on all
!root cpusets.
* cpuset_propagate_hotplug() is responsible for updating the specified
cpuset so that it doesn't include any resource which isn't available
to top_cpuset. If no CPU or memory is left after update, all tasks
are moved to the nearest ancestor with both resources.
* update_tasks_cpumask() and update_tasks_nodemask() are now always
called after cpus or mems masks are updated even if the cpuset
doesn't have any task. This is for brevity and not expected to have
any measureable effect.
* cpu_active_mask and N_HIGH_MEMORY are read exactly once per
cpuset_handle_hotplug() invocation, all cpusets share the same view
of what resources are available, and cpuset_handle_hotplug() can
handle multiple resources going up and down. These properties will
allow async operation.
The reorganization, while drastic, is equivalent and shouldn't cause
any behavior difference. This will enable making hotplug handling
async and remove get_online_cpus() -> cgroup_mutex nesting.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cpuset_can_attach() prepare global variables cpus_attach and
cpuset_attach_nodemask_{to|from} which are used by cpuset_attach().
There is no reason to prepare in cpuset_can_attach(). The same
information can be accessed from cpuset_attach().
Move the prepartion logic from cpuset_can_attach() to cpuset_attach()
and make the global variables static ones inside cpuset_attach().
With this change, there's no reason to keep
cpuset_attach_nodemask_{from|to} global. Move them inside
cpuset_attach(). Unfortunately, we need to keep cpus_attach global as
it can't be allocated from cpuset_attach().
v2: cpus_attach not converted to cpumask_t as per Li Zefan and Rusty
Russell.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Instead of iterating cgroup->children directly, introduce and use
cpuset_for_each_child() which wraps cgroup_for_each_child() and
performs online check. As it uses the generic iterator, it requires
RCU read locking too.
As cpuset is currently protected by cgroup_mutex, non-online cpusets
aren't visible to all the iterations and this patch currently doesn't
make any functional difference. This will be used to de-couple cpuset
locking from cgroup core.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Add CS_ONLINE which is set from css_online() and cleared from
css_offline(). This will enable using generic cgroup iterator while
allowing decoupling cpuset from cgroup internal locking.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Add cpuset_css_on/offline() and rearrange css init/exit such that,
* Allocation and clearing to the default values happen in css_alloc().
Allocation now uses kzalloc().
* Config inheritance and registration happen in css_online().
* css_offline() undoes what css_online() did.
* css_free() frees.
This doesn't introduce any visible behavior changes. This will help
cleaning up locking.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
The function isn't that hot, the overhead of missing the fast exit is
low, the test itself depends heavily on cgroup internals, and it's
gonna be a hindrance when trying to decouple cpuset locking from
cgroup core. Remove the fast exit path.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Implement cgroup_rightmost_descendant() which returns the right most
descendant of the specified cgroup. This can be used to skip the
cgroup's subtree while iterating with
cgroup_for_each_descendant_pre().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Merge emailed fixes from Andrew Morton:
"Bunch of fixes:
- delayed IPC updates. I held back on this because of some possible
outstanding bug reports, but they appear to have been addressed in
later versions
- A bunch of MAINTAINERS updates
- Yet Another RTC driver. I'd held this back while a couple of
little issues were being worked out.
I'm expecting an intrusive-but-simple patchset from Joe Perches which
splits up printk.c into kernel/printk/*. That will be a pig to
maintain for two months so if it passes testing I'd like to get it
upstream after a week or so."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits)
printk: fix incorrect length from print_time() when seconds > 99999
drivers/rtc/rtc-vt8500.c: fix handling of data passed in struct rtc_time
drivers/rtc/rtc-vt8500.c: correct handling of CR_24H bitfield
rtc: add RTC driver for TPS6586x
MAINTAINERS: fix drivers/staging/sm7xx/
MAINTAINERS: remove include/linux/of_pwm.h
MAINTAINERS: remove arch/*/lib/perf_event*.c
MAINTAINERS: remove drivers/mmc/host/imxmmc.*
MAINTAINERS: fix Documentation/mei/
MAINTAINERS: remove arch/x86/platform/mrst/pmu.*
MAINTAINERS: remove firmware/isci/
MAINTAINERS: fix drivers/ieee802154/
MAINTAINERS: fix .../plat-mxc/include/mach/imxfb.h
MAINTAINERS: remove drivers/video/epson1355fb.c
MAINTAINERS: fix drivers/media/usb/dvb-usb/cxusb*
MAINTAINERS: adjust for UAPI
MAINTAINERS: fix drivers/media/platform/atmel-isi.c
MAINTAINERS: fix arch/arm/mach-at91/include/mach/at_hdmac.h
MAINTAINERS: fix drivers/rtc/rtc-vt8500.c
MAINTAINERS: remove arch/arm/plat-s5p/
...
Cleanup. And I think we need more cleanups, in particular
__set_current_blocked() and sigprocmask() should die. Nobody should
ever block SIGKILL or SIGSTOP.
- Change set_current_blocked() to use __set_current_blocked()
- Change sys_sigprocmask() to use set_current_blocked(), this way it
should not worry about SIGKILL/SIGSTOP.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
print_prefix() passes a NULL buf to print_time() to get the length of
the time prefix; when printk times are enabled, the current code just
returns the constant 15, which matches the format "[%5lu.%06lu] " used
to print the time value. However, this is obviously incorrect when the
whole seconds part of the time gets beyond 5 digits (100000 seconds is a
bit more than a day of uptime).
The simple fix is to use snprintf(NULL, 0, ...) to calculate the actual
length of the time prefix. This could be micro-optimized but it seems
better to have simpler, more readable code here.
The bug leads to the syslog system call miscomputing which messages fit
into the userspace buffer. If there are enough messages to fill
log_buf_len and some have a timestamp >= 100000, dmesg may fail with:
# dmesg
klogctl: Bad address
When this happens, strace shows that the failure is indeed EFAULT due to
the kernel mistakenly accessing past the end of dmesg's buffer, since
dmesg asks the kernel how big a buffer it needs, allocates a bit more,
and then gets an error when it asks the kernel to fill it:
syslog(0xa, 0, 0) = 1048576
mmap(NULL, 1052672, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fa4d25d2000
syslog(0x3, 0x7fa4d25d2010, 0x100008) = -1 EFAULT (Bad address)
As far as I can see, the bug has been there as long as print_time(),
which comes from commit 084681d14e ("printk: flush continuation lines
immediately to console") in 3.5-rc5.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: Sylvain Munaut <s.munaut@whatever-company.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If we try to finit_module on a file sized 0 bytes vmalloc will
scream and spit out a warning.
Since modules have to be bigger than 0 bytes anyways we can just
check that beforehand and avoid the warning.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
In a container with its own pid namespace and user namespace, rebooting
the system won't reboot the host, but terminate all the processes in
it and thus have the container shutdown, so it's safe.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
It needs 64bit timespec. As it is, we end up truncating the timeout
to whole seconds; usually it doesn't matter, but for having all
sub-second timeouts truncated to one jiffy is visibly wrong.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It needs 64bit rusage and 32bit siginfo. glibc never calls it with
non-NULL rusage pointer, or we would've seen breakage already...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Strictly speaking, ppc64 needs it for C ABI compliance. Realistically
I would be very surprised if e.g. passing 0xffffffff as 'options'
argument to waitid() from 32bit task would cause problems, but yes,
it puts us into undefined behaviour territory. ppc64 expects int
argument to be passed in 64bit register with bits 31..63 containing
the same value. SYSCALL_DEFINE on ppc provides a wrapper that normalizes
the value passed from userland; so does COMPAT_SYSCALL_DEFINE. Plain
declaration of compat_sys_something() with an int argument obviously
doesn't. Again, for wait4 and waitid I would be extremely surprised
if gcc started to produce code depending on that value having been
properly sign-extended - the argument(s) in question end up passed
blindly to sys_wait4 and sys_waitid resp. and normalization for native
syscalls takes care of their use there. Still, better to use
COMPAT_SYSCALL_DEFINE here than worry about nasal daemons...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Oleg pointed out that in a pid namespace the sequence.
- pid 1 becomes a zombie
- setns(thepidns), fork,...
- reaping pid 1.
- The injected processes exiting.
Can lead to processes attempting access their child reaper and
instead following a stale pointer.
That waitpid for init can return before all of the processes in
the pid namespace have exited is also unfortunate.
Avoid these problems by disabling the allocation of new pids in a pid
namespace when init dies, instead of when the last process in a pid
namespace is reaped.
Pointed-out-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The sequence:
unshare(CLONE_NEWPID)
clone(CLONE_THREAD|CLONE_SIGHAND|CLONE_VM)
Creates a new process in the new pid namespace without setting
pid_ns->child_reaper. After forking this results in a NULL
pointer dereference.
Avoid this and other nonsense scenarios that can show up after
creating a new pid namespace with unshare by adding a new
check in copy_prodcess.
Pointed-out-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Currently, whenever CONFIG_ARCH_USES_GETTIMEOFFSET is enabled, each
arch core provides a single implementation of arch_gettimeoffset(). In
many cases, different sub-architectures, different machines, or
different timer providers exist, and so the arch ends up implementing
arch_gettimeoffset() as a call-through-pointer anyway. Examples are
ARM, Cris, M68K, and it's arguable that the remaining architectures,
M32R and Blackfin, should be doing this anyway.
Modify arch_gettimeoffset so that it itself is a function pointer, which
the arch initializes. This will allow later changes to move the
initialization of this function into individual machine support or timer
drivers. This is particularly useful for code in drivers/clocksource
which should rely on an arch-independant mechanism to register their
implementation of arch_gettimeoffset().
This patch also converts the Cris architecture to set arch_gettimeoffset
directly to the final implementation in time_init(), because Cris already
had separate time_init() functions per sub-architecture. M68K and ARM
are converted to set arch_gettimeoffset to the final implementation in
later patches, because they already have function pointers in place for
this purpose.
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Pull filesystem notification updates from Eric Paris:
"This pull mostly is about locking changes in the fsnotify system. By
switching the group lock from a spin_lock() to a mutex() we can now
hold the lock across things like iput(). This fixes a problem
involving unmounting a fs and having inodes be busy, first pointed out
by FAT, but reproducible with tmpfs.
This also restores signal driven I/O for inotify, which has been
broken since about 2.6.32."
Ugh. I *hate* the timing of this. It was rebased after the merge
window opened, and then left to sit with the pull request coming the day
before the merge window closes. That's just crap. But apparently the
patches themselves have been around for over a year, just gathering
dust, so now it's suddenly critical.
Fixed up semantic conflict in fs/notify/fdinfo.c as per Stephen
Rothwell's fixes from -next.
* 'for-next' of git://git.infradead.org/users/eparis/notify:
inotify: automatically restart syscalls
inotify: dont skip removal of watch descriptor if creation of ignored event failed
fanotify: dont merge permission events
fsnotify: make fasync generic for both inotify and fanotify
fsnotify: change locking order
fsnotify: dont put marks on temporary list when clearing marks by group
fsnotify: introduce locked versions of fsnotify_add_mark() and fsnotify_remove_mark()
fsnotify: pass group to fsnotify_destroy_mark()
fsnotify: use a mutex instead of a spinlock to protect a groups mark list
fanotify: add an extra flag to mark_remove_from_mask that indicates wheather a mark should be destroyed
fsnotify: take groups mark_lock before mark lock
fsnotify: use reference counting for groups
fsnotify: introduce fsnotify_get_group()
inotify, fanotify: replace fsnotify_put_group() with fsnotify_destroy_group()
Merge the rest of Andrew's patches for -rc1:
"A bunch of fixes and misc missed-out-on things.
That'll do for -rc1. I still have a batch of IPC patches which still
have a possible bug report which I'm chasing down."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (25 commits)
keys: use keyring_alloc() to create module signing keyring
keys: fix unreachable code
sendfile: allows bypassing of notifier events
SGI-XP: handle non-fatal traps
fat: fix incorrect function comment
Documentation: ABI: remove testing/sysfs-devices-node
proc: fix inconsistent lock state
linux/kernel.h: fix DIV_ROUND_CLOSEST with unsigned divisors
memcg: don't register hotcpu notifier from ->css_alloc()
checkpatch: warn on uapi #includes that #include <uapi/...
revert "rtc: recycle id when unloading a rtc driver"
mm: clean up transparent hugepage sysfs error messages
hfsplus: add error message for the case of failure of sync fs in delayed_sync_fs() method
hfsplus: rework processing of hfs_btree_write() returned error
hfsplus: rework processing errors in hfsplus_free_extents()
hfsplus: avoid crash on failed block map free
kcmp: include linux/ptrace.h
drivers/rtc/rtc-imxdi.c: must include <linux/spinlock.h>
mm: cma: WARN if freed memory is still in use
exec: do not leave bprm->interp on stack
...
Pull signal handling cleanups from Al Viro:
"sigaltstack infrastructure + conversion for x86, alpha and um,
COMPAT_SYSCALL_DEFINE infrastructure.
Note that there are several conflicts between "unify
SS_ONSTACK/SS_DISABLE definitions" and UAPI patches in mainline;
resolution is trivial - just remove definitions of SS_ONSTACK and
SS_DISABLED from arch/*/uapi/asm/signal.h; they are all identical and
include/uapi/linux/signal.h contains the unified variant."
Fixed up conflicts as per Al.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
alpha: switch to generic sigaltstack
new helpers: __save_altstack/__compat_save_altstack, switch x86 and um to those
generic compat_sys_sigaltstack()
introduce generic sys_sigaltstack(), switch x86 and um to it
new helper: compat_user_stack_pointer()
new helper: restore_altstack()
unify SS_ONSTACK/SS_DISABLE definitions
new helper: current_user_stack_pointer()
missing user_stack_pointer() instances
Bury the conditionals from kernel_thread/kernel_execve series
COMPAT_SYSCALL_DEFINE: infrastructure
Use keyring_alloc() to create special keyrings now that it has
a permissions parameter rather than using key_alloc() +
key_instantiate_and_link().
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This makes it compile on s390. After all the ptrace_may_access
(which we use this file) is declared exactly in linux/ptrace.h.
This is preparatory work to wire this syscall up on all archs.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Alexander Kartashov <alekskartashov@parallels.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
task_numa_placement() oopsed on NULL p->mm when task_numa_fault() got
called in the handling of break_ksm() for ksmd. That might be a
peculiar case, which perhaps KSM could takes steps to avoid? but it's
more robust if task_numa_placement() allows for such a possibility.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random
Pull random updates from Ted Ts'o:
"A few /dev/random improvements for the v3.8 merge window."
* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
random: Mix cputime from each thread that exits to the pool
random: prime last_data value per fips requirements
random: fix debug format strings
random: make it possible to enable debugging without rebuild
Conditional on CONFIG_GENERIC_SIGALTSTACK; architectures that do not
select it are completely unaffected
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
All architectures have
CONFIG_GENERIC_KERNEL_THREAD
CONFIG_GENERIC_KERNEL_EXECVE
__ARCH_WANT_SYS_EXECVE
None of them have __ARCH_WANT_KERNEL_EXECVE and there are only two callers
of kernel_execve() (which is a trivial wrapper for do_execve() now) left.
Kill the conditionals and make both callers use do_execve().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit 8d4516904b ("watchdog: Fix CPU hotplug regression") causes an
oops or hard lockup when doing
echo 0 > /proc/sys/kernel/nmi_watchdog
echo 1 > /proc/sys/kernel/nmi_watchdog
and the kernel is booted with nmi_watchdog=1 (default)
Running laptop-mode-tools and disconnecting/connecting AC power will
cause this to trigger, making it a common failure scenario on laptops.
Instead of bailing out of watchdog_disable() when !watchdog_enabled we
can initialize the hrtimer regardless of watchdog_enabled status. This
makes it safe to call watchdog_disable() in the nmi_watchdog=0 case,
without the negative effect on the enabled => disabled => enabled case.
All these tests pass with this patch:
- nmi_watchdog=1
echo 0 > /proc/sys/kernel/nmi_watchdog
echo 1 > /proc/sys/kernel/nmi_watchdog
- nmi_watchdog=0
echo 0 > /sys/devices/system/cpu/cpu1/online
- nmi_watchdog=0
echo mem > /sys/power/state
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=51661
Cc: <stable@vger.kernel.org> # v3.7
Cc: Norbert Warmuth <nwarmuth@t-online.de>
Cc: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
42f8570f43 ("workqueue: use new hashtable implementation") incorrectly
made busy workers hashed by the pointer value of worker instead of
work. This broke find_worker_executing_work() which in turn broke a
lot of fundamental operations of workqueue - non-reentrancy and
flushing among others. The flush malfunction triggered warning in
disk event code in Fengguang's automated test.
write_dev_root_ (3265) used greatest stack depth: 2704 bytes left
------------[ cut here ]------------
WARNING: at /c/kernel-tests/src/stable/block/genhd.c:1574 disk_clear_events+0x\
cf/0x108()
Hardware name: Bochs
Modules linked in:
Pid: 3328, comm: ata_id Not tainted 3.7.0-01930-gbff6343 #1167
Call Trace:
[<ffffffff810997c4>] warn_slowpath_common+0x83/0x9c
[<ffffffff810997f7>] warn_slowpath_null+0x1a/0x1c
[<ffffffff816aea77>] disk_clear_events+0xcf/0x108
[<ffffffff811bd8be>] check_disk_change+0x27/0x59
[<ffffffff822e48e2>] cdrom_open+0x49/0x68b
[<ffffffff81ab0291>] idecd_open+0x88/0xb7
[<ffffffff811be58f>] __blkdev_get+0x102/0x3ec
[<ffffffff811bea08>] blkdev_get+0x18f/0x30f
[<ffffffff811bebfd>] blkdev_open+0x75/0x80
[<ffffffff8118f510>] do_dentry_open+0x1ea/0x295
[<ffffffff8118f5f0>] finish_open+0x35/0x41
[<ffffffff8119c720>] do_last+0x878/0xa25
[<ffffffff8119c993>] path_openat+0xc6/0x333
[<ffffffff8119cf37>] do_filp_open+0x38/0x86
[<ffffffff81190170>] do_sys_open+0x6c/0xf9
[<ffffffff8119021e>] sys_open+0x21/0x23
[<ffffffff82c1c3d9>] system_call_fastpath+0x16/0x1b
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
to verify the source of the module (ChromeOS) and/or use standard IMA on it
or other security hooks.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module update from Rusty Russell:
"Nothing all that exciting; a new module-from-fd syscall for those who
want to verify the source of the module (ChromeOS) and/or use standard
IMA on it or other security hooks."
* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
MODSIGN: Fix kbuild output when using default extra_certificates
MODSIGN: Avoid using .incbin in C source
modules: don't hand 0 to vmalloc.
module: Remove a extra null character at the top of module->strtab.
ASN.1: Use the ASN1_LONG_TAG and ASN1_INDEFINITE_LENGTH constants
ASN.1: Define indefinite length marker constant
moduleparam: use __UNIQUE_ID()
__UNIQUE_ID()
MODSIGN: Add modules_sign make target
powerpc: add finit_module syscall.
ima: support new kernel module syscall
add finit_module syscall to asm-generic
ARM: add finit_module syscall to ARM
security: introduce kernel_module_from_file hook
module: add flags arg to sys_finit_module()
module: add syscall to load module from fd
Merge patches from Andrew Morton:
"Most of the rest of MM, plus a few dribs and drabs.
I still have quite a few irritating patches left around: ones with
dubious testing results, lack of review, ones which should have gone
via maintainer trees but the maintainers are slack, etc.
I need to be more activist in getting these things wrapped up outside
the merge window, but they're such a PITA."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (48 commits)
mm/vmscan.c: avoid possible deadlock caused by too_many_isolated()
vmscan: comment too_many_isolated()
mm/kmemleak.c: remove obsolete simple_strtoul
mm/memory_hotplug.c: improve comments
mm/hugetlb: create hugetlb cgroup file in hugetlb_init
mm/mprotect.c: coding-style cleanups
Documentation: ABI: /sys/devices/system/node/
slub: drop mutex before deleting sysfs entry
memcg: add comments clarifying aspects of cache attribute propagation
kmem: add slab-specific documentation about the kmem controller
slub: slub-specific propagation changes
slab: propagate tunable values
memcg: aggregate memcg cache values in slabinfo
memcg/sl[au]b: shrink dead caches
memcg/sl[au]b: track all the memcg children of a kmem_cache
memcg: destroy memcg caches
sl[au]b: allocate objects from memcg cache
sl[au]b: always get the cache from its page in kmem_cache_free()
memcg: skip memcg kmem allocations in specified code regions
memcg: infrastructure to match an allocation to the right cache
...
Because those architectures will draw their stacks directly from the page
allocator, rather than the slab cache, we can directly pass __GFP_KMEMCG
flag, and issue the corresponding free_pages.
This code path is taken when the architecture doesn't define
CONFIG_ARCH_THREAD_INFO_ALLOCATOR (only ia64 seems to), and has
THREAD_SIZE >= PAGE_SIZE. Luckily, most - if not all - of the remaining
architectures fall in this category.
This will guarantee that every stack page is accounted to the memcg the
process currently lives on, and will have the allocations to fail if they
go over limit.
For the time being, I am defining a new variant of THREADINFO_GFP, not to
mess with the other path. Once the slab is also tracked by memcg, we can
get rid of that flag.
Tested to successfully protect against :(){ :|:& };:
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Frederic Weisbecker <fweisbec@redhat.com>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is useful to know how many charges are still left after a call to
res_counter_uncharge. While it is possible to issue a res_counter_read
after uncharge, this can be racy.
If we need, for instance, to take some action when the counters drop down
to 0, only one of the callers should see it. This is the same semantics
as the atomic variables in the kernel.
Since the current return value is void, we don't need to worry about
anything breaking due to this change: nobody relied on that, and only
users appearing from now on will be checking this value.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The array check is useless so remove it.
[akpm@linux-foundation.org: remove comment, per David]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull minor tracing updates and fixes from Steven Rostedt:
"It seems that one of my old pull requests have slipped through.
The changes are contained to just the files that I maintain, and are
changes from others that I told I would get into this merge window.
They have already been in linux-next for several weeks, and should be
well tested."
* 'tip/perf/core-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Remove unnecessary WARN_ONCE's from tracing_buffers_splice_read
tracing: Remove unneeded checks from the stack tracer
tracing: Add a resize function to make one buffer equivalent to another buffer
To avoid executing the same work item concurrenlty, workqueue hashes
currently busy workers according to their current work items and looks
up the the table when it wants to execute a new work item. If there
already is a worker which is executing the new work item, the new item
is queued to the found worker so that it gets executed only after the
current execution finishes.
Unfortunately, a work item may be freed while being executed and thus
recycled for different purposes. If it gets recycled for a different
work item and queued while the previous execution is still in
progress, workqueue may make the new work item wait for the old one
although the two aren't really related in any way.
In extreme cases, this false dependency may lead to deadlock although
it's extremely unlikely given that there aren't too many self-freeing
work item users and they usually don't wait for other work items.
To alleviate the problem, record the current work function in each
busy worker and match it together with the work item address in
find_worker_executing_work(). While this isn't complete, it ensures
that unrelated work items don't interact with each other and in the
very unlikely case where a twisted wq user triggers it, it's always
onto itself making the culprit easy to spot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Andrey Isakov <andy51@gmx.ru>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=51701
Cc: stable@vger.kernel.org
Pull (again) user namespace infrastructure changes from Eric Biederman:
"Those bugs, those darn embarrasing bugs just want don't want to get
fixed.
Linus I just updated my mirror of your kernel.org tree and it appears
you successfully pulled everything except the last 4 commits that fix
those embarrasing bugs.
When you get a chance can you please repull my branch"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
userns: Fix typo in description of the limitation of userns_install
userns: Add a more complete capability subset test to commit_creds
userns: Require CAP_SYS_ADMIN for most uses of setns.
Fix cap_capable to only allow owners in the parent user namespace to have caps.
Switch workqueues to use the new hashtable implementation. This reduces the
amount of generic unrelated code in the workqueues.
This patch depends on d9b482c ("hashtable: introduce a small and naive
hashtable") which was merged in v3.6.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Merge misc patches from Andrew Morton:
"Incoming:
- lots of misc stuff
- backlight tree updates
- lib/ updates
- Oleg's percpu-rwsem changes
- checkpatch
- rtc
- aoe
- more checkpoint/restart support
I still have a pile of MM stuff pending - Pekka should be merging
later today after which that is good to go. A number of other things
are twiddling thumbs awaiting maintainer merges."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (180 commits)
scatterlist: don't BUG when we can trivially return a proper error.
docs: update documentation about /proc/<pid>/fdinfo/<fd> fanotify output
fs, fanotify: add @mflags field to fanotify output
docs: add documentation about /proc/<pid>/fdinfo/<fd> output
fs, notify: add procfs fdinfo helper
fs, exportfs: add exportfs_encode_inode_fh() helper
fs, exportfs: escape nil dereference if no s_export_op present
fs, epoll: add procfs fdinfo helper
fs, eventfd: add procfs fdinfo helper
procfs: add ability to plug in auxiliary fdinfo providers
tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test
breakpoint selftests: print failure status instead of cause make error
kcmp selftests: print fail status instead of cause make error
kcmp selftests: make run_tests fix
mem-hotplug selftests: print failure status instead of cause make error
cpu-hotplug selftests: print failure status instead of cause make error
mqueue selftests: print failure status instead of cause make error
vm selftests: print failure status instead of cause make error
ubifs: use prandom_bytes
mtd: nandsim: use prandom_bytes
...
Ptrace jailers want to be sure that the tracee can never escape
from the control. However if the tracer dies unexpectedly the
tracee continues to run in potentially unsafe mode.
Add the new ptrace option PTRACE_O_EXITKILL. If the tracer exits
it sends SIGKILL to every tracee which has this bit set.
Note that the new option is not equal to the last-option << 1. Because
currently all options have an event, and the new one starts the eventless
group. It uses the random 20 bit, so we have the room for 12 more events,
but we can also add the new eventless options below this one.
Suggested by Amnon Shiloh.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Amnon Shiloh <u3557@miso.sublimeip.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: Chris Evans <scarybeasts@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function is used by sparc, powerpc tile and arm64 for compat support.
The patch adds a generic implementation with a wrapper for PowerPC to do
the u32->int sign extension.
The reason for a single patch covering powerpc, tile, sparc and arm64 is
to keep it bisectable, otherwise kernel building may fail with mismatched
function declarations.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com> [for tile]
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The boot_delay parameter affects all printk(), even if the log level
prevents visible output from the call. It results in delays greater than
the user intended without purpose.
This patch changes the behaviour of boot_delay to only delay output.
Signed-off-by: Andrew Cooks <acooks@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently getting the sample period is always thru a complex
calculation: get_softlockup_thresh() * ((u64)NSEC_PER_SEC / 5).
We can store the sample period as a variable, and set it as __read_mostly
type.
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Cc: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
But the kernel decided to call it "origin" instead. Fix most of the
sites.
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit 9c0ece069b ("Get rid of Documentation/feature-removal.txt"),
Linus removed feature-removal-schedule.txt from Documentation, but there
is still some reference to this file. So remove them.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull user namespace changes from Eric Biederman:
"While small this set of changes is very significant with respect to
containers in general and user namespaces in particular. The user
space interface is now complete.
This set of changes adds support for unprivileged users to create user
namespaces and as a user namespace root to create other namespaces.
The tyranny of supporting suid root preventing unprivileged users from
using cool new kernel features is broken.
This set of changes completes the work on setns, adding support for
the pid, user, mount namespaces.
This set of changes includes a bunch of basic pid namespace
cleanups/simplifications. Of particular significance is the rework of
the pid namespace cleanup so it no longer requires sending out
tendrils into all kinds of unexpected cleanup paths for operation. At
least one case of broken error handling is fixed by this cleanup.
The files under /proc/<pid>/ns/ have been converted from regular files
to magic symlinks which prevents incorrect caching by the VFS,
ensuring the files always refer to the namespace the process is
currently using and ensuring that the ptrace_mayaccess permission
checks are always applied.
The files under /proc/<pid>/ns/ have been given stable inode numbers
so it is now possible to see if different processes share the same
namespaces.
Through the David Miller's net tree are changes to relax many of the
permission checks in the networking stack to allowing the user
namespace root to usefully use the networking stack. Similar changes
for the mount namespace and the pid namespace are coming through my
tree.
Two small changes to add user namespace support were commited here adn
in David Miller's -net tree so that I could complete the work on the
/proc/<pid>/ns/ files in this tree.
Work remains to make it safe to build user namespaces and 9p, afs,
ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the
Kconfig guard remains in place preventing that user namespaces from
being built when any of those filesystems are enabled.
Future design work remains to allow root users outside of the initial
user namespace to mount more than just /proc and /sys."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits)
proc: Usable inode numbers for the namespace file descriptors.
proc: Fix the namespace inode permission checks.
proc: Generalize proc inode allocation
userns: Allow unprivilged mounts of proc and sysfs
userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file
procfs: Print task uids and gids in the userns that opened the proc file
userns: Implement unshare of the user namespace
userns: Implent proc namespace operations
userns: Kill task_user_ns
userns: Make create_new_namespaces take a user_ns parameter
userns: Allow unprivileged use of setns.
userns: Allow unprivileged users to create new namespaces
userns: Allow setting a userns mapping to your current uid.
userns: Allow chown and setgid preservation
userns: Allow unprivileged users to create user namespaces.
userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped
userns: fix return value on mntns_install() failure
vfs: Allow unprivileged manipulation of the mount namespace.
vfs: Only support slave subtrees across different user namespaces
vfs: Add a user namespace reference from struct mnt_namespace
...
Michal Hocko reported that the following build error occurs if
CONFIG_NUMA_BALANCING is set without THP support
kernel/sched/fair.c: In function ‘task_numa_work’:
kernel/sched/fair.c:932:55: error: call to ‘__build_bug_failed’ declared with attribute error: BUILD_BUG failed
The problem is that HPAGE_PMD_SHIFT triggers a BUILD_BUG() on
!CONFIG_TRANSPARENT_HUGEPAGE. This patch addresses the problem.
Reported-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a thread exits mix it's cputime (userspace + kernelspace) to the entropy pool.
We don't know how "random" this is, so we use add_device_randomness that doesn't mess
with entropy count.
Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Pull security subsystem updates from James Morris:
"A quiet cycle for the security subsystem with just a few maintenance
updates."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
Smack: create a sysfs mount point for smackfs
Smack: use select not depends in Kconfig
Yama: remove locking from delete path
Yama: add RCU to drop read locking
drivers/char/tpm: remove tasklet and cleanup
KEYS: Use keyring_alloc() to create special keyrings
KEYS: Reduce initial permissions on keys
KEYS: Make the session and process keyrings per-thread
seccomp: Make syscall skipping and nr changes more consistent
key: Fix resource leak
keys: Fix unreachable code
KEYS: Add payload preparsing opportunity prior to key instantiate or update
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Merge tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma
Pull Automatic NUMA Balancing bare-bones from Mel Gorman:
"There are three implementations for NUMA balancing, this tree
(balancenuma), numacore which has been developed in tip/master and
autonuma which is in aa.git.
In almost all respects balancenuma is the dumbest of the three because
its main impact is on the VM side with no attempt to be smart about
scheduling. In the interest of getting the ball rolling, it would be
desirable to see this much merged for 3.8 with the view to building
scheduler smarts on top and adapting the VM where required for 3.9.
The most recent set of comparisons available from different people are
mel: https://lkml.org/lkml/2012/12/9/108
mingo: https://lkml.org/lkml/2012/12/7/331
tglx: https://lkml.org/lkml/2012/12/10/437
srikar: https://lkml.org/lkml/2012/12/10/397
The results are a mixed bag. In my own tests, balancenuma does
reasonably well. It's dumb as rocks and does not regress against
mainline. On the other hand, Ingo's tests shows that balancenuma is
incapable of converging for this workloads driven by perf which is bad
but is potentially explained by the lack of scheduler smarts. Thomas'
results show balancenuma improves on mainline but falls far short of
numacore or autonuma. Srikar's results indicate we all suffer on a
large machine with imbalanced node sizes.
My own testing showed that recent numacore results have improved
dramatically, particularly in the last week but not universally.
We've butted heads heavily on system CPU usage and high levels of
migration even when it shows that overall performance is better.
There are also cases where it regresses. Of interest is that for
specjbb in some configurations it will regress for lower numbers of
warehouses and show gains for higher numbers which is not reported by
the tool by default and sometimes missed in treports. Recently I
reported for numacore that the JVM was crashing with
NullPointerExceptions but currently it's unclear what the source of
this problem is. Initially I thought it was in how numacore batch
handles PTEs but I'm no longer think this is the case. It's possible
numacore is just able to trigger it due to higher rates of migration.
These reports were quite late in the cycle so I/we would like to start
with this tree as it contains much of the code we can agree on and has
not changed significantly over the last 2-3 weeks."
* tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits)
mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable
mm/rmap: Convert the struct anon_vma::mutex to an rwsem
mm: migrate: Account a transhuge page properly when rate limiting
mm: numa: Account for failed allocations and isolations as migration failures
mm: numa: Add THP migration for the NUMA working set scanning fault case build fix
mm: numa: Add THP migration for the NUMA working set scanning fault case.
mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node
mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG
mm: sched: numa: Control enabling and disabling of NUMA balancing
mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate
mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely task<->node relationships
mm: numa: migrate: Set last_nid on newly allocated page
mm: numa: split_huge_page: Transfer last_nid on tail page
mm: numa: Introduce last_nid to the page frame
sched: numa: Slowly increase the scanning period as NUMA faults are handled
mm: numa: Rate limit setting of pte_numa if node is saturated
mm: numa: Rate limit the amount of memory that is migrated between nodes
mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting
mm: numa: Migrate pages handled during a pmd_numa hinting fault
mm: numa: Migrate on reference policy
...
When unsharing a user namespace we reduce our credentials to just what
can be done in that user namespace. This is a subset of the credentials
we previously had. Teach commit_creds to recognize this is a subset
of the credentials we have had before and don't clear the dumpability flag.
This allows an unprivileged program to do:
unshare(CLONE_NEWUSER);
fd = open("/proc/self/uid_map", O_RDWR);
Where previously opening the uid_map writable would fail because
the the task had been made non-dumpable.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Andy Lutomirski <luto@amacapital.net> found a nasty little bug in
the permissions of setns. With unprivileged user namespaces it
became possible to create new namespaces without privilege.
However the setns calls were relaxed to only require CAP_SYS_ADMIN in
the user nameapce of the targed namespace.
Which made the following nasty sequence possible.
pid = clone(CLONE_NEWUSER | CLONE_NEWNS);
if (pid == 0) { /* child */
system("mount --bind /home/me/passwd /etc/passwd");
}
else if (pid != 0) { /* parent */
char path[PATH_MAX];
snprintf(path, sizeof(path), "/proc/%u/ns/mnt");
fd = open(path, O_RDONLY);
setns(fd, 0);
system("su -");
}
Prevent this possibility by requiring CAP_SYS_ADMIN
in the current user namespace when joing all but the user namespace.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This reverts commit f269ae0469.
It turns out it causes a very noticeable interactivity regression with
CONFIG_SCHED_AUTOGROUP (test-case: "make -j32" of the kernel in a
terminal window, while scrolling in a browser - the autogrouping means
that the two end up in separate cgroups, and the browser should be
smooth as silk despite the high load).
Says Paul Turner:
"It seems that the update-throttling on the wake-side is reducing the
interactive tasks' ability to preempt. While I suspect the right
longer term answer here is force these updates only in the
cross-cgroup case; this is less trivial. For this release I believe
the right answer is either going to be a revert or restore the updates
on the enqueue-side."
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Bisected-by: Mike Galbraith <efault@gmx.de>
Acked-by: Paul Turner <pjt@google.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Peter Foley <pefoley2@verizon.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: Peter Foley <pefoley2@verizon.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Using the asm .incbin statement in C sources breaks any gcc wrapper which
assumes that preprocessed C source is self-contained. Use a separate .S
file to include the siging key and certificate.
[ This means we no longer need SYMBOL_PREFIX which is defined in kernel.h
from cbdbf2abb7, so I removed it -- RR ]
Tested-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: James Hogan <james.hogan@imgtec.com>
In commit d0a21265df David Rientjes unified various archs'
module_alloc implementation (including x86) and removed the graduitous
shortcut for size == 0.
Then, in commit de7d2b567d, Joe Perches added a warning for
zero-length vmallocs, which can happen without kallsyms on modules
with no init sections (eg. zlib_deflate).
Fix this once and for all; the module code has to handle zero length
anyway, so get it right at the caller and remove the now-gratuitous
checks within the arch-specific module_alloc implementations.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=42608
Reported-by: Conrad Kostecki <ConiKost@gmx.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
There is a extra null character('\0') at the top of module->strtab for
each module. Commit 59ef28b introduced this bug and this patch fixes it.
Live dump log of the current linus git kernel(HEAD is 2844a4870):
============================================================================
crash> mod | grep loop
ffffffffa01db0a0 loop 16689 (not loaded) [CONFIG_KALLSYMS]
crash> module.core_symtab ffffffffa01db0a0
core_symtab = 0xffffffffa01db320crash> rd 0xffffffffa01db320 12
ffffffffa01db320: 0000005500000001 0000000000000000 ....U...........
ffffffffa01db330: 0000000000000000 0002007400000002 ............t...
ffffffffa01db340: ffffffffa01d8000 0000000000000038 ........8.......
ffffffffa01db350: 001a00640000000e ffffffffa01daeb0 ....d...........
ffffffffa01db360: 00000000000000a0 0002007400000019 ............t...
ffffffffa01db370: ffffffffa01d8068 000000000000001b h...............
crash> module.core_strtab ffffffffa01db0a0
core_strtab = 0xffffffffa01dbb30 ""
crash> rd 0xffffffffa01dbb30 4
ffffffffa01dbb30: 615f70616d6b0000 66780063696d6f74 ..kmap_atomic.xf
ffffffffa01dbb40: 73636e75665f7265 72665f646e696600 er_funcs.find_fr
============================================================================
We expect Just first one byte of '\0', but actually first two bytes
are '\0'. Here is The relationship between symtab and strtab.
symtab_idx strtab_idx symbol
-----------------------------------------------
0 0x1 "\0" # startab_idx should be 0
1 0x2 "kmap_atomic"
2 0xe "xfer_funcs"
3 0x19 "find_fr..."
By applying this patch, it becomes as follows.
symtab_idx strtab_idx symbol
-----------------------------------------------
0 0x0 "\0" # extra byte is removed
1 0x1 "kmap_atomic"
2 0xd "xfer_funcs"
3 0x18 "find_fr..."
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Cc: Masaki Kimura <masaki.kimura.kz@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Now that kernel module origins can be reasoned about, provide a hook to
the LSMs to make policy decisions about the module file. This will let
Chrome OS enforce that loadable kernel modules can only come from its
read-only hash-verified root filesystem. Other LSMs can, for example,
read extended attributes for signatures, etc.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Thanks to Michael Kerrisk for keeping us honest. These flags are actually
useful for eliminating the only case where kmod has to mangle a module's
internals: for overriding module versioning.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Acked-by: Kees Cook <keescook@chromium.org>
As part of the effort to create a stronger boundary between root and
kernel, Chrome OS wants to be able to enforce that kernel modules are
being loaded only from our read-only crypto-hash verified (dm_verity)
root filesystem. Since the init_module syscall hands the kernel a module
as a memory blob, no reasoning about the origin of the blob can be made.
Earlier proposals for appending signatures to kernel modules would not be
useful in Chrome OS, since it would involve adding an additional set of
keys to our kernel and builds for no good reason: we already trust the
contents of our root filesystem. We don't need to verify those kernel
modules a second time. Having to do signature checking on module loading
would slow us down and be redundant. All we need to know is where a
module is coming from so we can say yes/no to loading it.
If a file descriptor is used as the source of a kernel module, many more
things can be reasoned about. In Chrome OS's case, we could enforce that
the module lives on the filesystem we expect it to live on. In the case
of IMA (or other LSMs), it would be possible, for example, to examine
extended attributes that may contain signatures over the contents of
the module.
This introduces a new syscall (on x86), similar to init_module, that has
only two arguments. The first argument is used as a file descriptor to
the module and the second argument is a pointer to the NULL terminated
string of module arguments.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (merge fixes)
Pull KVM updates from Marcelo Tosatti:
"Considerable KVM/PPC work, x86 kvmclock vsyscall support,
IA32_TSC_ADJUST MSR emulation, amongst others."
Fix up trivial conflict in kernel/sched/core.c due to cross-cpu
migration notifier added next to rq migration call-back.
* tag 'kvm-3.8-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (156 commits)
KVM: emulator: fix real mode segment checks in address linearization
VMX: remove unneeded enable_unrestricted_guest check
KVM: VMX: fix DPL during entry to protected mode
x86/kexec: crash_vmclear_local_vmcss needs __rcu
kvm: Fix irqfd resampler list walk
KVM: VMX: provide the vmclear function and a bitmap to support VMCLEAR in kdump
x86/kexec: VMCLEAR VMCSs loaded on all cpus if necessary
KVM: MMU: optimize for set_spte
KVM: PPC: booke: Get/set guest EPCR register using ONE_REG interface
KVM: PPC: bookehv: Add EPCR support in mtspr/mfspr emulation
KVM: PPC: bookehv: Add guest computation mode for irq delivery
KVM: PPC: Make EPCR a valid field for booke64 and bookehv
KVM: PPC: booke: Extend MAS2 EPN mask for 64-bit
KVM: PPC: e500: Mask MAS2 EPN high 32-bits in 32/64 tlbwe emulation
KVM: PPC: Mask ea's high 32-bits in 32/64 instr emulation
KVM: PPC: e500: Add emulation helper for getting instruction ea
KVM: PPC: bookehv64: Add support for interrupt handling
KVM: PPC: bookehv: Remove GET_VCPU macro from exception handler
KVM: PPC: booke: Fix get_tb() compile error on 64-bit
KVM: PPC: e500: Silence bogus GCC warning in tlb code
...
Merge misc VM changes from Andrew Morton:
"The rest of most-of-MM. The other MM bits await a slab merge.
This patch includes the addition of a huge zero_page. Not a
performance boost but it an save large amounts of physical memory in
some situations.
Also a bunch of Fujitsu engineers are working on memory hotplug.
Which, as it turns out, was badly broken. About half of their patches
are included here; the remainder are 3.8 material."
However, this merge disables CONFIG_MOVABLE_NODE, which was totally
broken. We don't add new features with "default y", nor do we add
Kconfig questions that are incomprehensible to most people without any
help text. Does the feature even make sense without compaction or
memory hotplug?
* akpm: (54 commits)
mm/bootmem.c: remove unused wrapper function reserve_bootmem_generic()
mm/memory.c: remove unused code from do_wp_page()
asm-generic, mm: pgtable: consolidate zero page helpers
mm/hugetlb.c: fix warning on freeing hwpoisoned hugepage
hwpoison, hugetlbfs: fix RSS-counter warning
hwpoison, hugetlbfs: fix "bad pmd" warning in unmapping hwpoisoned hugepage
mm: protect against concurrent vma expansion
memcg: do not check for mm in __mem_cgroup_count_vm_event
tmpfs: support SEEK_DATA and SEEK_HOLE (reprise)
mm: provide more accurate estimation of pages occupied by memmap
fs/buffer.c: remove redundant initialization in alloc_page_buffers()
fs/buffer.c: do not inline exported function
writeback: fix a typo in comment
mm: introduce new field "managed_pages" to struct zone
mm, oom: remove statically defined arch functions of same name
mm, oom: remove redundant sleep in pagefault oom handler
mm, oom: cleanup pagefault oom handler
memory_hotplug: allow online/offline memory to result movable node
numa: add CONFIG_MOVABLE_NODE for movable-dedicated node
mm, memcg: avoid unnecessary function call when memcg is disabled
...
Pull trivial branch from Jiri Kosina:
"Usual stuff -- comment/printk typo fixes, documentation updates, dead
code elimination."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
HOWTO: fix double words typo
x86 mtrr: fix comment typo in mtrr_bp_init
propagate name change to comments in kernel source
doc: Update the name of profiling based on sysfs
treewide: Fix typos in various drivers
treewide: Fix typos in various Kconfig
wireless: mwifiex: Fix typo in wireless/mwifiex driver
messages: i2o: Fix typo in messages/i2o
scripts/kernel-doc: check that non-void fcts describe their return value
Kernel-doc: Convention: Use a "Return" section to describe return values
radeon: Fix typo and copy/paste error in comments
doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c
various: Fix spelling of "asynchronous" in comments.
Fix misspellings of "whether" in comments.
eisa: Fix spelling of "asynchronous".
various: Fix spelling of "registered" in comments.
doc: fix quite a few typos within Documentation
target: iscsi: fix comment typos in target/iscsi drivers
treewide: fix typo of "suport" in various comments and Kconfig
treewide: fix typo of "suppport" in various comments
...
Pull networking changes from David Miller:
1) Allow to dump, monitor, and change the bridge multicast database
using netlink. From Cong Wang.
2) RFC 5961 TCP blind data injection attack mitigation, from Eric
Dumazet.
3) Networking user namespace support from Eric W. Biederman.
4) tuntap/virtio-net multiqueue support by Jason Wang.
5) Support for checksum offload of encapsulated packets (basically,
tunneled traffic can still be checksummed by HW). From Joseph
Gasparakis.
6) Allow BPF filter access to VLAN tags, from Eric Dumazet and
Daniel Borkmann.
7) Bridge port parameters over netlink and BPDU blocking support
from Stephen Hemminger.
8) Improve data access patterns during inet socket demux by rearranging
socket layout, from Eric Dumazet.
9) TIPC protocol updates and cleanups from Ying Xue, Paul Gortmaker, and
Jon Maloy.
10) Update TCP socket hash sizing to be more in line with current day
realities. The existing heurstics were choosen a decade ago.
From Eric Dumazet.
11) Fix races, queue bloat, and excessive wakeups in ATM and
associated drivers, from Krzysztof Mazur and David Woodhouse.
12) Support DOVE (Distributed Overlay Virtual Ethernet) extensions
in VXLAN driver, from David Stevens.
13) Add "oops_only" mode to netconsole, from Amerigo Wang.
14) Support set and query of VEB/VEPA bridge mode via PF_BRIDGE, also
allow DCB netlink to work on namespaces other than the initial
namespace. From John Fastabend.
15) Support PTP in the Tigon3 driver, from Matt Carlson.
16) tun/vhost zero copy fixes and improvements, plus turn it on
by default, from Michael S. Tsirkin.
17) Support per-association statistics in SCTP, from Michele
Baldessari.
And many, many, driver updates, cleanups, and improvements. Too
numerous to mention individually.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1722 commits)
net/mlx4_en: Add support for destination MAC in steering rules
net/mlx4_en: Use generic etherdevice.h functions.
net: ethtool: Add destination MAC address to flow steering API
bridge: add support of adding and deleting mdb entries
bridge: notify mdb changes via netlink
ndisc: Unexport ndisc_{build,send}_skb().
uapi: add missing netconf.h to export list
pkt_sched: avoid requeues if possible
solos-pci: fix double-free of TX skb in DMA mode
bnx2: Fix accidental reversions.
bna: Driver Version Updated to 3.1.2.1
bna: Firmware update
bna: Add RX State
bna: Rx Page Based Allocation
bna: TX Intr Coalescing Fix
bna: Tx and Rx Optimizations
bna: Code Cleanup and Enhancements
ath9k: check pdata variable before dereferencing it
ath5k: RX timestamp is reported at end of frame
ath9k_htc: RX timestamp is reported at end of frame
...
N_HIGH_MEMORY stands for the nodes that has normal or high memory.
N_MEMORY stands for the nodes that has any memory.
The code here need to handle with the nodes which have memory, we should
use N_MEMORY instead.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Lin Feng <linfeng@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
N_HIGH_MEMORY stands for the nodes that has normal or high memory.
N_MEMORY stands for the nodes that has any memory.
The code here need to handle with the nodes which have memory, we should
use N_MEMORY instead.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Lin Feng <linfeng@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull big execve/kernel_thread/fork unification series from Al Viro:
"All architectures are converted to new model. Quite a bit of that
stuff is actually shared with architecture trees; in such cases it's
literally shared branch pulled by both, not a cherry-pick.
A lot of ugliness and black magic is gone (-3KLoC total in this one):
- kernel_thread()/kernel_execve()/sys_execve() redesign.
We don't do syscalls from kernel anymore for either kernel_thread()
or kernel_execve():
kernel_thread() is essentially clone(2) with callback run before we
return to userland, the callbacks either never return or do
successful do_execve() before returning.
kernel_execve() is a wrapper for do_execve() - it doesn't need to
do transition to user mode anymore.
As a result kernel_thread() and kernel_execve() are
arch-independent now - they live in kernel/fork.c and fs/exec.c
resp. sys_execve() is also in fs/exec.c and it's completely
architecture-independent.
- daemonize() is gone, along with its parts in fs/*.c
- struct pt_regs * is no longer passed to do_fork/copy_process/
copy_thread/do_execve/search_binary_handler/->load_binary/do_coredump.
- sys_fork()/sys_vfork()/sys_clone() unified; some architectures
still need wrappers (ones with callee-saved registers not saved in
pt_regs on syscall entry), but the main part of those suckers is in
kernel/fork.c now."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (113 commits)
do_coredump(): get rid of pt_regs argument
print_fatal_signal(): get rid of pt_regs argument
ptrace_signal(): get rid of unused arguments
get rid of ptrace_signal_deliver() arguments
new helper: signal_pt_regs()
unify default ptrace_signal_deliver
flagday: kill pt_regs argument of do_fork()
death to idle_regs()
don't pass regs to copy_process()
flagday: don't pass regs to copy_thread()
bfin: switch to generic vfork, get rid of pointless wrappers
xtensa: switch to generic clone()
openrisc: switch to use of generic fork and clone
unicore32: switch to generic clone(2)
score: switch to generic fork/vfork/clone
c6x: sanitize copy_thread(), get rid of clone(2) wrapper, switch to generic clone()
take sys_fork/sys_vfork/sys_clone prototypes to linux/syscalls.h
mn10300: switch to generic fork/vfork/clone
h8300: switch to generic fork/vfork/clone
tile: switch to generic clone()
...
Conflicts:
arch/microblaze/include/asm/Kbuild
Pull cgroup changes from Tejun Heo:
"A lot of activities on cgroup side. The big changes are focused on
making cgroup hierarchy handling saner.
- cgroup_rmdir() had peculiar semantics - it allowed cgroup
destruction to be vetoed by individual controllers and tried to
drain refcnt synchronously. The vetoing never worked properly and
caused good deal of contortions in cgroup. memcg was the last
reamining user. Michal Hocko removed the usage and cgroup_rmdir()
path has been simplified significantly. This was done in a
separate branch so that the memcg people can base further memcg
changes on top.
- The above allowed cleaning up cgroup lifecycle management and
implementation of generic cgroup iterators which are used to
improve hierarchy support.
- cgroup_freezer updated to allow migration in and out of a frozen
cgroup and handle hierarchy. If a cgroup is frozen, all descendant
cgroups are frozen.
- netcls_cgroup and netprio_cgroup updated to handle hierarchy
properly.
- Various fixes and cleanups.
- Two merge commits. One to pull in memcg and rmdir cleanups (needed
to build iterators). The other pulled in cgroup/for-3.7-fixes for
device_cgroup fixes so that further device_cgroup patches can be
stacked on top."
Fixed up a trivial conflict in mm/memcontrol.c as per Tejun (due to
commit bea8c150a7 ("memcg: fix hotplugged memory zone oops") in master
touching code close to commit 2ef37d3fe4 ("memcg: Simplify
mem_cgroup_force_empty_list error handling") in for-3.8)
* 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (65 commits)
cgroup: update Documentation/cgroups/00-INDEX
cgroup_rm_file: don't delete the uncreated files
cgroup: remove subsystem files when remounting cgroup
cgroup: use cgroup_addrm_files() in cgroup_clear_directory()
cgroup: warn about broken hierarchies only after css_online
cgroup: list_del_init() on removed events
cgroup: fix lockdep warning for event_control
cgroup: move list add after list head initilization
netprio_cgroup: allow nesting and inherit config on cgroup creation
netprio_cgroup: implement netprio[_set]_prio() helpers
netprio_cgroup: use cgroup->id instead of cgroup_netprio_state->prioidx
netprio_cgroup: reimplement priomap expansion
netprio_cgroup: shorten variable names in extend_netdev_table()
netprio_cgroup: simplify write_priomap()
netcls_cgroup: move config inheritance to ->css_online() and remove .broken_hierarchy marking
cgroup: remove obsolete guarantee from cgroup_task_migrate.
cgroup: add cgroup->id
cgroup, cpuset: remove cgroup_subsys->post_clone()
cgroup: s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/
cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free()
...
Pull workqueue changes from Tejun Heo:
"Nothing exciting. Just two trivial changes."
* 'for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: add WARN_ON_ONCE() on CPU number to wq_worker_waking_up()
workqueue: trivial fix for return statement in work_busy()
Pull x86 BSP hotplug changes from Ingo Molnar:
"This tree enables CPU#0 (the boot processor) to be onlined/offlined on
x86, just like any other CPU. Enabled on Intel CPUs for now.
Allowing this required the identification and fixing of latent CPU#0
assumptions (such as CPU#0 initializations, etc.) in the x86
architecture code, plus the identification of barriers to
BSP-offlining, such as active PIC interrupts which can only be
serviced on the BSP.
It's behind a default-off option, and there's a debug option that
allows the automatic testing of this feature.
The motivation of this feature is to allow and prepare for true
CPU-hotplug hardware support: recent changes to MCE support enable us
to detect a deteriorating but not yet hard-failing L1/L2 cache on a
CPU that could be soft-unplugged - or a failing L3 cache on a
multi-socket system.
Note that true hardware hot-plug is not yet fully enabled by this,
because that requires a special platform wakeup sequence to be sent to
the freshly powered up CPU#0. Future patches for this are planned,
once such a platform exists. Chicken and egg"
* 'x86-bsp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, topology: Debug CPU0 hotplug
x86/i387.c: Initialize thread xstate only on CPU0 only once
x86, hotplug: Handle retrigger irq by the first available CPU
x86, hotplug: The first online processor saves the MTRR state
x86, hotplug: During CPU0 online, enable x2apic, set_numa_node.
x86, hotplug: Wake up CPU0 via NMI instead of INIT, SIPI, SIPI
x86-32, hotplug: Add start_cpu0() entry point to head_32.S
x86-64, hotplug: Add start_cpu0() entry point to head_64.S
kernel/cpu.c: Add comment for priority in cpu_hotplug_pm_callback
x86, hotplug, suspend: Online CPU0 for suspend or hibernate
x86, hotplug: Support functions for CPU0 online/offline
x86, topology: Don't offline CPU0 if any PIC irq can not be migrated out of it
x86, Kconfig: Add config switch for CPU0 hotplug
doc: Add x86 CPU0 online/offline feature
Pull core timer changes from Ingo Molnar:
"It contains continued generic-NOHZ work by Frederic and smaller
cleanups."
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: Kill xtime_lock, replacing it with jiffies_lock
clocksource: arm_generic: use this_cpu_ptr per-cpu helper
clocksource: arm_generic: use integer math helpers
time/jiffies: Make clocksource_jiffies static
clocksource: clean up parse_pmtmr()
tick: Correct the comments for tick_sched_timer()
tick: Conditionally build nohz specific code in tick handler
tick: Consolidate tick handling for high and low res handlers
tick: Consolidate timekeeping handling code
Pull scheduler updates from Ingo Molnar:
"The biggest change affects group scheduling: we now track the runnable
average on a per-task entity basis, allowing a smoother, exponential
decay average based load/weight estimation instead of the previous
binary on-the-runqueue/off-the-runqueue load weight method.
This will inevitably disturb workloads that were in some sort of
borderline balancing state or unstable equilibrium, so an eye has to
be kept on regressions.
For that reason the new load average is only limited to group
scheduling (shares distribution) at the moment (which was also hurting
the most from the prior, crude weight calculation and whose scheduling
quality wins most from this change) - but we plan to extend this to
regular SMP balancing as well in the future, which will simplify and
speed up things a bit.
Other changes involve ongoing preparatory work to extend NOHZ to the
scheduler as well, eventually allowing completely irq-free user-space
execution."
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled"
cputime: Comment cputime's adjusting code
cputime: Consolidate cputime adjustment code
cputime: Rename thread_group_times to thread_group_cputime_adjusted
cputime: Move thread_group_cputime() to sched code
vtime: Warn if irqs aren't disabled on system time accounting APIs
vtime: No need to disable irqs on vtime_account()
vtime: Consolidate a bit the ctx switch code
vtime: Explicitly account pending user time on process tick
vtime: Remove the underscore prefix invasion
sched/autogroup: Fix crash on reboot when autogroup is disabled
cputime: Separate irqtime accounting from generic vtime
cputime: Specialize irq vtime hooks
kvm: Directly account vtime to system on guest switch
vtime: Make vtime_account_system() irqsafe
vtime: Gather vtime declarations to their own header file
sched: Describe CFS load-balancer
sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking
sched: Make __update_entity_runnable_avg() fast
sched: Update_cfs_shares at period edge
...
Pull perf fixes from Ingo Molnar:
"These are late-v3.7 pending fixes for tracing."
Fix up trivial conflict in kernel/trace/ring_buffer.c: the NULL pointer
fix clashed with the change of type of the 'ret' variable.
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ring-buffer: Fix race between integrity check and readers
ring-buffer: Fix NULL pointer if rb_set_head_page() fails
ftrace: Clear bits properly in reset_iter_read()
Pull perf updates from Ingo Molnar:
"Lots of activity:
211 files changed, 8328 insertions(+), 4116 deletions(-)
most of it on the tooling side.
Main changes:
* ftrace enhancements and fixes from Steve Rostedt.
* uprobes fixes, cleanups and preparation for the ARM port from Oleg
Nesterov.
* UAPI fixes, from David Howels - prepares the arch/x86 UAPI
transition
* Separate perf tests into multiple objects, one per test, from Jiri
Olsa.
* Make hardware event translations available in sysfs, from Jiri
Olsa.
* Fixes to /proc/pid/maps parsing, preparatory to supporting data
maps, from Namhyung Kim
* Implement ui_progress for GTK, from Namhyung Kim
* Add framework for automated perf_event_attr tests, where tools with
different command line options will be run from a 'perf test', via
python glue, and the perf syscall will be intercepted to verify
that the perf_event_attr fields set by the tool are those expected,
from Jiri Olsa
* Add a 'link' method for hists, so that we can have the leader with
buckets for all the entries in all the hists. This new method is
now used in the default 'diff' output, making the sum of the
'baseline' column be 100%, eliminating blind spots.
* libtraceevent fixes for compiler warnings trying to make perf it
build on some distros, like fedora 14, 32-bit, some of the warnings
really pointed to real bugs.
* Add a browser for 'perf script' and make it available from the
report and annotate browsers. It does filtering to find the
scripts that handle events found in the perf.data file used. From
Feng Tang
* perf inject changes to allow showing where a task sleeps, from
Andrew Vagin.
* Makefile improvements from Namhyung Kim.
* Add --pre and --post command hooks in 'stat', from Peter Zijlstra.
* Don't stop synthesizing threads when one vanishes, this is for the
existing threads when we start a tool like trace.
* Use sched:sched_stat_runtime to provide a thread summary, this
produces the same output as the 'trace summary' subcommand of
tglx's original "trace" tool.
* Support interrupted syscalls in 'trace'
* Add an event duration column and filter in 'trace'.
* There are references to the man pages in some tools, so try to
build Documentation when installing, warning the user if that is
not possible, from Borislav Petkov.
* Give user better message if precise is not supported, from David
Ahern.
* Try to find cross-built objdump path by using the session
environment information in the perf.data file header, from Irina
Tirdea, original patch and idea by Namhyung Kim.
* Diplays more output on features check for make V=1, so that one can
figure out what is happening by looking at gcc output, etc. From
Jiri Olsa.
* Add on_exit implementation for systems without one, e.g. Android,
from Bernhard Rosenkraenzer.
* Only process events for vcpus of interest, helps handling large
number of events, from David Ahern.
* Cross compilation fixes for Android, from Irina Tirdea.
* Add documentation on compiling for Android, from Irina Tirdea.
* perf diff improvements from Jiri Olsa.
* Target (task/user/cpu/syswide) handling improvements, from Namhyung
Kim.
* Add support in 'trace' for tracing workload given by command line,
from Namhyung Kim.
* ... and much more."
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (194 commits)
uprobes: Use percpu_rw_semaphore to fix register/unregister vs dup_mmap() race
perf evsel: Introduce is_group_member method
perf powerpc: Use uapi/unistd.h to fix build error
tools: Pass the target in descend
tools: Honour the O= flag when tool build called from a higher Makefile
tools: Define a Makefile function to do subdir processing
perf ui: Always compile browser setup code
perf ui: Add ui_progress__finish()
perf ui gtk: Implement ui_progress functions
perf ui: Introduce generic ui_progress helper
perf ui tui: Move progress.c under ui/tui directory
perf tools: Add basic event modifier sanity check
perf tools: Omit group members from perf_evlist__disable/enable
perf tools: Ensure single disable call per event in record comand
perf tools: Fix 'disabled' attribute config for record command
perf tools: Fix attributes for '{}' defined event groups
perf tools: Use sscanf for parsing /proc/pid/maps
perf tools: Add gtk.<command> config option for launching GTK browser
perf tools: Fix compile error on NO_NEWT=1 build
perf hists: Initialize all of he->stat with zeroes
...
Pull irq fixes from Ingo Molnar:
"Affinity fixes and a nested threaded IRQ handling fix."
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Always force thread affinity
irq: Set CPU affinity right on thread creation
genirq: Provide means to retrigger parent
Pull RCU update from Ingo Molnar:
"The major features of this tree are:
1. A first version of no-callbacks CPUs. This version prohibits
offlining CPU 0, but only when enabled via CONFIG_RCU_NOCB_CPU=y.
Relaxing this constraint is in progress, but not yet ready
for prime time. These commits were posted to LKML at
https://lkml.org/lkml/2012/10/30/724.
2. Changes to SRCU that allows statically initialized srcu_struct
structures. These commits were posted to LKML at
https://lkml.org/lkml/2012/10/30/296.
3. Restructuring of RCU's debugfs output. These commits were posted
to LKML at https://lkml.org/lkml/2012/10/30/341.
4. Additional CPU-hotplug/RCU improvements, posted to LKML at
https://lkml.org/lkml/2012/10/30/327.
Note that the commit eliminating __stop_machine() was judged to
be too-high of risk, so is deferred to 3.9.
5. Changes to RCU's idle interface, most notably a new module
parameter that redirects normal grace-period operations to
their expedited equivalents. These were posted to LKML at
https://lkml.org/lkml/2012/10/30/739.
6. Additional diagnostics for RCU's CPU stall warning facility,
posted to LKML at https://lkml.org/lkml/2012/10/30/315.
The most notable change reduces the
default RCU CPU stall-warning time from 60 seconds to 21 seconds,
so that it once again happens sooner than the softlockup timeout.
7. Documentation updates, which were posted to LKML at
https://lkml.org/lkml/2012/10/30/280.
A couple of late-breaking changes were posted at
https://lkml.org/lkml/2012/11/16/634 and
https://lkml.org/lkml/2012/11/16/547.
8. Miscellaneous fixes, which were posted to LKML at
https://lkml.org/lkml/2012/10/30/309.
9. Finally, a fix for an lockdep-RCU splat was posted to LKML
at https://lkml.org/lkml/2012/11/7/486."
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (49 commits)
context_tracking: New context tracking susbsystem
sched: Mark RCU reader in sched_show_task()
rcu: Separate accounting of callbacks from callback-free CPUs
rcu: Add callback-free CPUs
rcu: Add documentation for the new rcuexp debugfs trace file
rcu: Update documentation for TREE_RCU debugfs tracing
rcu: Reduce default RCU CPU stall warning timeout
rcu: Fix TINY_RCU rcu_is_cpu_rrupt_from_idle check
rcu: Clarify memory-ordering properties of grace-period primitives
rcu: Add new rcutorture module parameters to start/end test messages
rcu: Remove list_for_each_continue_rcu()
rcu: Fix batch-limit size problem
rcu: Add tracing for synchronize_sched_expedited()
rcu: Remove old debugfs interfaces and also RCU flavor name
rcu: split 'rcuhier' to each flavor
rcu: split 'rcugp' to each flavor
rcu: split 'rcuboost' to each flavor
rcu: split 'rcubarrier' to each flavor
rcu: Fix tracing formatting
rcu: Remove the interface "rcudata.csv"
...
Pull trivial fix branches from Ingo Molnar.
Cleanup in __get_key_name, and a timer comment fixlet.
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep: Use KSYM_NAME_LEN'ed buffer for __get_key_name()
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers, sched: Correct the comments for tick_sched_timer()
Here's the big tty/serial tree set of changes for 3.8-rc1.
Contained in here is a bunch more reworks of the tty port layer from Jiri and
bugfixes from Alan, along with a number of other tty and serial driver updates
by the various driver authors.
Also, Jiri has been coerced^Wconvinced to be the co-maintainer of the TTY
layer, which is much appreciated by me.
All of these have been in the linux-next tree for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull TTY/Serial merge from Greg Kroah-Hartman:
"Here's the big tty/serial tree set of changes for 3.8-rc1.
Contained in here is a bunch more reworks of the tty port layer from
Jiri and bugfixes from Alan, along with a number of other tty and
serial driver updates by the various driver authors.
Also, Jiri has been coerced^Wconvinced to be the co-maintainer of the
TTY layer, which is much appreciated by me.
All of these have been in the linux-next tree for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
Fixed up some trivial conflicts in the staging tree, due to the fwserial
driver having come in both ways (but fixed up a bit in the serial tree),
and the ioctl handling in the dgrp driver having been done slightly
differently (staging tree got that one right, and removed both
TIOCGSOFTCAR and TIOCSSOFTCAR).
* tag 'tty-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (146 commits)
staging: sb105x: fix potential NULL pointer dereference in mp_chars_in_buffer()
staging/fwserial: Remove superfluous free
staging/fwserial: Use WARN_ONCE when port table is corrupted
staging/fwserial: Destruct embedded tty_port on teardown
staging/fwserial: Fix build breakage when !CONFIG_BUG
staging: fwserial: Add TTY-over-Firewire serial driver
drivers/tty/serial/serial_core.c: clean up HIGH_BITS_OFFSET usage
staging: dgrp: dgrp_tty.c: Audit the return values of get/put_user()
staging: dgrp: dgrp_tty.c: Remove the TIOCSSOFTCAR ioctl handler from dgrp driver
serial: ifx6x60: Add modem power off function in the platform reboot process
serial: mxs-auart: unmap the scatter list before we copy the data
serial: mxs-auart: disable the Receive Timeout Interrupt when DMA is enabled
serial: max310x: Setup missing "can_sleep" field for GPIO
tty/serial: fix ifx6x60.c declaration warning
serial: samsung: add devicetree properties for non-Exynos SoCs
serial: samsung: fix potential soft lockup during uart write
tty: vt: Remove redundant null check before kfree.
tty/8250 Add check for pci_ioremap_bar failure
tty/8250 Add support for Commtech's Fastcom Async-335 and Fastcom Async-PCIe cards
tty/8250 Add XR17D15x devices to the exar_handle_irq override
...
Here's the large driver core updates for 3.8-rc1.
The biggest thing here is the various __dev* marking removals. This is
going to be a pain for the merge with different subsystem trees, I know,
but all of the patches included here have been ACKed by their various
subsystem maintainers, as they wanted them to go through here.
If this is too much of a pain, I can pull all of them out of this tree
and just send you one with the other fixes/updates and then, after
3.8-rc1 is out, do the rest of the removals to ensure we catch them all,
it's up to you. The merges should all be trivial, and Stephen has been
doing them all in linux-next for a few weeks now quite easily.
Other than the __dev* marking removals, there's nothing major here, some
firmware loading updates and other minor things in the driver core.
All of these have (much to Stephen's annoyance), been in linux-next for
a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg Kroah-Hartman:
"Here's the large driver core updates for 3.8-rc1.
The biggest thing here is the various __dev* marking removals. This
is going to be a pain for the merge with different subsystem trees, I
know, but all of the patches included here have been ACKed by their
various subsystem maintainers, as they wanted them to go through here.
If this is too much of a pain, I can pull all of them out of this tree
and just send you one with the other fixes/updates and then, after
3.8-rc1 is out, do the rest of the removals to ensure we catch them
all, it's up to you. The merges should all be trivial, and Stephen
has been doing them all in linux-next for a few weeks now quite
easily.
Other than the __dev* marking removals, there's nothing major here,
some firmware loading updates and other minor things in the driver
core.
All of these have (much to Stephen's annoyance), been in linux-next
for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
Fixed up trivial conflicts in drivers/gpio/gpio-{em,stmpe}.c due to gpio
update.
* tag 'driver-core-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (93 commits)
modpost.c: Stop checking __dev* section mismatches
init.h: Remove __dev* sections from the kernel
acpi: remove use of __devinit
PCI: Remove __dev* markings
PCI: Always build setup-bus when PCI is enabled
PCI: Move pci_uevent into pci-driver.c
PCI: Remove CONFIG_HOTPLUG ifdefs
unicore32/PCI: Remove CONFIG_HOTPLUG ifdefs
sh/PCI: Remove CONFIG_HOTPLUG ifdefs
powerpc/PCI: Remove CONFIG_HOTPLUG ifdefs
mips/PCI: Remove CONFIG_HOTPLUG ifdefs
microblaze/PCI: Remove CONFIG_HOTPLUG ifdefs
dma: remove use of __devinit
dma: remove use of __devexit_p
firewire: remove use of __devinitdata
firewire: remove use of __devinit
leds: remove use of __devexit
leds: remove use of __devinit
leds: remove use of __devexit_p
mmc: remove use of __devexit
...
* Introduction of device PM QoS flags.
* ACPI device power management update allowing subsystems other than
PCI to use it more easily.
* ACPI device enumeration rework allowing additional kinds of devices
to be enumerated via ACPI. From Mika Westerberg, Adrian Hunter,
Mathias Nyman, Andy Shevchenko, and Rafael J. Wysocki.
* ACPICA update to version 20121018 from Bob Moore and Lv Zheng.
* ACPI memory hotplug update from Wen Congyang and Yasuaki Ishimatsu.
* Introduction of acpi_handle_<level>() messaging macros and ACPI-based CPU
hot-remove support from Toshi Kani.
* ACPI EC updates from Feng Tang.
* cpufreq updates from Viresh Kumar, Fabio Baltieri and others.
* cpuidle changes to quickly notice governor prediction failure from
Youquan Song.
* Support for using multiple cpuidle drivers at the same time and cpuidle
cleanups from Daniel Lezcano.
* devfreq updates from Nishanth Menon and others.
* cpupower update from Thomas Renninger.
* Fixes and small cleanups all over the place.
--
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Merge tag 'pm+acpi-for-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management updates from Rafael Wysocki:
- Introduction of device PM QoS flags.
- ACPI device power management update allowing subsystems other than
PCI to use it more easily.
- ACPI device enumeration rework allowing additional kinds of devices
to be enumerated via ACPI. From Mika Westerberg, Adrian Hunter,
Mathias Nyman, Andy Shevchenko, and Rafael J. Wysocki.
- ACPICA update to version 20121018 from Bob Moore and Lv Zheng.
- ACPI memory hotplug update from Wen Congyang and Yasuaki Ishimatsu.
- Introduction of acpi_handle_<level>() messaging macros and ACPI-based
CPU hot-remove support from Toshi Kani.
- ACPI EC updates from Feng Tang.
- cpufreq updates from Viresh Kumar, Fabio Baltieri and others.
- cpuidle changes to quickly notice governor prediction failure from
Youquan Song.
- Support for using multiple cpuidle drivers at the same time and
cpuidle cleanups from Daniel Lezcano.
- devfreq updates from Nishanth Menon and others.
- cpupower update from Thomas Renninger.
- Fixes and small cleanups all over the place.
* tag 'pm+acpi-for-3.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (196 commits)
mmc: sdhci-acpi: enable runtime-pm for device HID INT33C6
ACPI: add Haswell LPSS devices to acpi_platform_device_ids list
ACPI: add documentation about ACPI 5 enumeration
pnpacpi: fix incorrect TEST_ALPHA() test
ACPI / PM: Fix header of acpi_dev_pm_detach() in acpi.h
ACPI / video: ignore BIOS initial backlight value for HP Folio 13-2000
ACPI : do not use Lid and Sleep button for S5 wakeup
ACPI / PNP: Do not crash due to stale pointer use during system resume
ACPI / video: Add "Asus UL30VT" to ACPI video detect blacklist
ACPI: do acpisleep dmi check when CONFIG_ACPI_SLEEP is set
spi / ACPI: add ACPI enumeration support
gpio / ACPI: add ACPI support
PM / devfreq: remove compiler error with module governors (2)
cpupower: IvyBridge (0x3a and 0x3e models) support
cpupower: Provide -c param for cpupower monitor to schedule process on all cores
cpupower tools: Fix warning and a bug with the cpu package count
cpupower tools: Fix malloc of cpu_info structure
cpupower tools: Fix issues with sysfs_topology_read_file
cpupower tools: Fix minor warnings
cpupower tools: Update .gitignore for files created in the debug directories
...
Trivial changes to irqdomain. An update to the documentation and make
one of the error paths not quite so obnoxious.
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Merge tag 'irqdomain-for-linus' of git://git.secretlab.ca/git/linux-2.6
Pull irqdomain changes from Grant Likely:
"Trivial changes to irqdomain. An update to the documentation and make
one of the error paths not quite so obnoxious."
* tag 'irqdomain-for-linus' of git://git.secretlab.ca/git/linux-2.6:
irqdomain: update documentation
irqdomain: stop screaming about preallocated irqdescs
In fsnotify_destroy_mark() dont get the group from the passed mark anymore,
but pass the group itself as an additional parameter to the function.
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
Due to the fact that migrations are driven by the CPU a task is running
on there is no point tracking NUMA faults until one task runs on a new
node. This patch tracks the first node used by an address space. Until
it changes, PTE scanning is disabled and no NUMA hinting faults are
trapped. This should help workloads that are short-lived, do not care
about NUMA placement or have bound themselves to a single node.
This takes advantage of the logic in "mm: sched: numa: Implement slow
start for working set sampling" to delay when the checks are made. This
will take advantage of processes that set their CPU and node bindings
early in their lifetime. It will also potentially allow any initial load
balancing to take place.
Signed-off-by: Mel Gorman <mgorman@suse.de>
The "mm: sched: numa: Control enabling and disabling of NUMA balancing"
depends on scheduling debug being enabled but it's perfectly legimate to
disable automatic NUMA balancing even without this option. This should
take care of it.
Signed-off-by: Mel Gorman <mgorman@suse.de>
This patch adds Kconfig options and kernel parameters to allow the
enabling and disabling of automatic NUMA balancing. The existance
of such a switch was and is very important when debugging problems
related to transparent hugepages and we should have the same for
automatic NUMA placement.
Signed-off-by: Mel Gorman <mgorman@suse.de>
The PTE scanning rate and fault rates are two of the biggest sources of
system CPU overhead with automatic NUMA placement. Ideally a proper policy
would detect if a workload was properly placed, schedule and adjust the
PTE scanning rate accordingly. We do not track the necessary information
to do that but we at least know if we migrated or not.
This patch scans slower if a page was not migrated as the result of a
NUMA hinting fault up to sysctl_numa_balancing_scan_period_max which is
now higher than the previous default. Once every minute it will reset
the scanner in case of phase changes.
This is hilariously crude and the numbers are arbitrary. Workloads will
converge quite slowly in comparison to what a proper policy should be able
to do. On the plus side, we will chew up less CPU for workloads that have
no need for automatic balancing.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Currently the rate of scanning for an address space is controlled
by the individual tasks. The next scan is simply determined by
2*p->numa_scan_period.
The 2*p->numa_scan_period is arbitrary and never changes. At this point
there is still no proper policy that decides if a task or process is
properly placed. It just scans and assumes the next NUMA fault will
place it properly. As it is assumed that pages will get properly placed
over time, increase the scan window each time a fault is incurred. This
is a big assumption as noted in the comments.
It should be noted that changing to p->numa_scan_period will increase
system CPU usage because now the scanning rate has effectively doubled.
If that is a problem then the min_rate should be made 200ms instead of
restoring the 2* logic.
Signed-off-by: Mel Gorman <mgorman@suse.de>
If there are a large number of NUMA hinting faults and all of them
are resulting in migrations it may indicate that memory is just
bouncing uselessly around. NUMA balancing cost is likely exceeding
any benefit from locality. Rate limit the PTE updates if the node
is migration rate-limited. As noted in the comments, this distorts
the NUMA faulting statistics.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Add a 1 second delay before starting to scan the working set of
a task and starting to balance it amongst nodes.
[ note that before the constant per task WSS sampling rate patch
the initial scan would happen much later still, in effect that
patch caused this regression. ]
The theory is that short-run tasks benefit very little from NUMA
placement: they come and go, and they better stick to the node
they were started on. As tasks mature and rebalance to other CPUs
and nodes, so does their NUMA placement have to change and so
does it start to matter more and more.
In practice this change fixes an observable kbuild regression:
# [ a perf stat --null --repeat 10 test of ten bzImage builds to /dev/shm ]
!NUMA:
45.291088843 seconds time elapsed ( +- 0.40% )
45.154231752 seconds time elapsed ( +- 0.36% )
+NUMA, no slow start:
46.172308123 seconds time elapsed ( +- 0.30% )
46.343168745 seconds time elapsed ( +- 0.25% )
+NUMA, 1 sec slow start:
45.224189155 seconds time elapsed ( +- 0.25% )
45.160866532 seconds time elapsed ( +- 0.17% )
and it also fixes an observable perf bench (hackbench) regression:
# perf stat --null --repeat 10 perf bench sched messaging
-NUMA:
-NUMA: 0.246225691 seconds time elapsed ( +- 1.31% )
+NUMA no slow start: 0.252620063 seconds time elapsed ( +- 1.13% )
+NUMA 1sec delay: 0.248076230 seconds time elapsed ( +- 1.35% )
The implementation is simple and straightforward, most of the patch
deals with adding the /proc/sys/kernel/numa_balancing_scan_delay_ms tunable
knob.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
[ Wrote the changelog, ran measurements, tuned the default. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Previously, to probe the working set of a task, we'd use
a very simple and crude method: mark all of its address
space PROT_NONE.
That method has various (obvious) disadvantages:
- it samples the working set at dissimilar rates,
giving some tasks a sampling quality advantage
over others.
- creates performance problems for tasks with very
large working sets
- over-samples processes with large address spaces but
which only very rarely execute
Improve that method by keeping a rotating offset into the
address space that marks the current position of the scan,
and advance it by a constant rate (in a CPU cycles execution
proportional manner). If the offset reaches the last mapped
address of the mm then it then it starts over at the first
address.
The per-task nature of the working set sampling functionality in this tree
allows such constant rate, per task, execution-weight proportional sampling
of the working set, with an adaptive sampling interval/frequency that
goes from once per 100ms up to just once per 8 seconds. The current
sampling volume is 256 MB per interval.
As tasks mature and converge their working set, so does the
sampling rate slow down to just a trickle, 256 MB per 8
seconds of CPU time executed.
This, beyond being adaptive, also rate-limits rarely
executing systems and does not over-sample on overloaded
systems.
[ In AutoNUMA speak, this patch deals with the effective sampling
rate of the 'hinting page fault'. AutoNUMA's scanning is
currently rate-limited, but it is also fundamentally
single-threaded, executing in the knuma_scand kernel thread,
so the limit in AutoNUMA is global and does not scale up with
the number of CPUs, nor does it scan tasks in an execution
proportional manner.
So the idea of rate-limiting the scanning was first implemented
in the AutoNUMA tree via a global rate limit. This patch goes
beyond that by implementing an execution rate proportional
working set sampling rate that is not implemented via a single
global scanning daemon. ]
[ Dan Carpenter pointed out a possible NULL pointer dereference in the
first version of this patch. ]
Based-on-idea-by: Andrea Arcangeli <aarcange@redhat.com>
Bug-Found-By: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
[ Wrote changelog and fixed bug. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
NOTE: This patch is based on "sched, numa, mm: Add fault driven
placement and migration policy" but as it throws away all the policy
to just leave a basic foundation I had to drop the signed-offs-by.
This patch creates a bare-bones method for setting PTEs pte_numa in the
context of the scheduler that when faulted later will be faulted onto the
node the CPU is running on. In itself this does nothing useful but any
placement policy will fundamentally depend on receiving hints on placement
from fault context and doing something intelligent about it.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
commit 52553ddf(genirq: fix regression in irqfixup, irqpoll)
introduced a potential deadlock by calling the action handler with the
irq descriptor lock held.
Remove the call and let the handling code run even for an interrupt
where only a single action is registered. That matches the goal of
the above commit and avoids the deadlock.
Document the confusing action = desc->action reload in the handling
loop while at it.
Reported-and-tested-by: "Wang, Warner" <warner.wang@hp.com>
Tested-by: Edward Donovan <edward.donovan@numble.net>
Cc: "Wang, Song-Bo (Stoney)" <song-bo.wang@hp.com>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
in cgroup_add_file,when creating files for cgroup,
some of creation may be skipped. So we need to avoid
deleting these uncreated files in cgroup_rm_file,
otherwise the warning msg will be triggered.
"cgroup_addrm_files: failed to remove memory_pressure_enabled, err=-2"
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@redhat.com>
Cc: stable@vger.kernel.org
Pull module signing fixes from Rusty Russell:
"David gave me these a month ago, during my git workflow churn :("
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
ASN.1: Fix an indefinite length skip error
MODSIGN: Don't use enum-type bitfields in module signature info block
Pull watchdog fix from Thomas Gleixner:
"Trivial CPU hotplug regression fix for the watchdog code"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
watchdog: Fix CPU hotplug regression
I've legally changed my name with New York State, the US Social Security
Administration, et al. This patch propagates the name change and change
in initials and login to comments in the kernel source as well.
Signed-off-by: Nadia Yvette Chambers <nyc@holomorphy.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Don't use enum-type bitfields in the module signature info block as we can't be
certain how the compiler will handle them. As I understand it, it is arch
dependent, and it is possible for the compiler to rearrange them based on
endianness and to insert a byte of padding to pad the three enums out to four
bytes.
Instead use u8 fields for these, which the compiler should emit in the right
order without padding.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Norbert reported:
"3.7-rc6 booted with nmi_watchdog=0 fails to suspend to RAM or
offline CPUs. It's reproducable with a KVM guest and physical
system."
The reason is that commit bcd951cf(watchdog: Use hotplug thread
infrastructure) missed to take this into account. So the cpu offline
code gets stuck in the teardown function because it accesses non
initialized data structures.
Add a check for watchdog_enabled into that path to cure the issue.
Reported-and-tested-by: Norbert Warmuth <nwarmuth@t-online.de>
Tested-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1211231033230.2701@ionos
Link: http://bugs.launchpad.net/bugs/1079534
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull module fixes from Rusty Russell:
"Module signing build fixes for blackfin and metag"
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
modsign: add symbol prefix to certificate list
linux/kernel.h: define SYMBOL_PREFIX
Pull workqueue fixes from Tejun Heo:
"So, safe fixes my ass.
Commit 8852aac25e ("workqueue: mod_delayed_work_on() shouldn't queue
timer on 0 delay") had the side-effect of performing delayed_work
sanity checks even when @delay is 0, which should be fine for any sane
use cases.
Unfortunately, megaraid was being overly ingenious. It seemingly
wanted to use cancel_delayed_work_sync() before cancel_work_sync() was
introduced, but didn't want to waste the space for full delayed_work
as it was only going to use 0 @delay. So, it only allocated space for
struct work_struct and then cast it to struct delayed_work and passed
it into delayed_work functions - truly awesome engineering tradeoff to
save some bytes.
Xiaotian fixed it by making megraid allocate full delayed_work for
now. It should be converted to use work_struct and cancel_work_sync()
but I think we better do that after 3.7.
I added another commit to change BUG_ON()s in __queue_delayed_work()
to WARN_ON_ONCE()s so that the kernel doesn't crash even if there are
more such abuses."
* 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: convert BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s
megaraid: fix BUG_ON() from incorrect use of delayed work
8852aac25e ("workqueue: mod_delayed_work_on() shouldn't queue timer on
0 delay") unexpectedly uncovered a very nasty abuse of delayed_work in
megaraid - it allocated work_struct, casted it to delayed_work and
then pass that into queue_delayed_work().
Previously, this was okay because 0 @delay short-circuited to
queue_work() before doing anything with delayed_work. 8852aac25e
moved 0 @delay test into __queue_delayed_work() after sanity check on
delayed_work making megaraid trigger BUG_ON().
Although megaraid is already fixed by c1d390d8e6 ("megaraid: fix
BUG_ON() from incorrect use of delayed work"), this patch converts
BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s so that such
abusers, if there are more, trigger warning but don't crash the
machine.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Xiaotian Feng <xtfeng@gmail.com>
cgroup_clear_directroy is called by cgroup_d_remove_dir
and cgroup_remount.
when we call cgroup_remount to remount the cgroup,the subsystem
may be unlinked from cgroupfs_root->subsys_list in rebind_subsystem,this
subsystem's files will not be removed in cgroup_clear_directroy.
And the system will panic when we try to access these files.
this patch removes subsystems's files before rebind_subsystems,
if rebind_subsystems failed, repopulate these removed files.
With help from Tejun.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Conflicts:
arch/x86/kernel/ptrace.c
Pull the latest RCU tree from Paul E. McKenney:
" The major features of this series are:
1. A first version of no-callbacks CPUs. This version prohibits
offlining CPU 0, but only when enabled via CONFIG_RCU_NOCB_CPU=y.
Relaxing this constraint is in progress, but not yet ready
for prime time. These commits were posted to LKML at
https://lkml.org/lkml/2012/10/30/724, and are at branch rcu/nocb.
2. Changes to SRCU that allows statically initialized srcu_struct
structures. These commits were posted to LKML at
https://lkml.org/lkml/2012/10/30/296, and are at branch rcu/srcu.
3. Restructuring of RCU's debugfs output. These commits were posted
to LKML at https://lkml.org/lkml/2012/10/30/341, and are at
branch rcu/tracing.
4. Additional CPU-hotplug/RCU improvements, posted to LKML at
https://lkml.org/lkml/2012/10/30/327, and are at branch rcu/hotplug.
Note that the commit eliminating __stop_machine() was judged to
be too-high of risk, so is deferred to 3.9.
5. Changes to RCU's idle interface, most notably a new module
parameter that redirects normal grace-period operations to
their expedited equivalents. These were posted to LKML at
https://lkml.org/lkml/2012/10/30/739, and are at branch rcu/idle.
6. Additional diagnostics for RCU's CPU stall warning facility,
posted to LKML at https://lkml.org/lkml/2012/10/30/315, and
are at branch rcu/stall. The most notable change reduces the
default RCU CPU stall-warning time from 60 seconds to 21 seconds,
so that it once again happens sooner than the softlockup timeout.
7. Documentation updates, which were posted to LKML at
https://lkml.org/lkml/2012/10/30/280, and are at branch rcu/doc.
A couple of late-breaking changes were posted at
https://lkml.org/lkml/2012/11/16/634 and
https://lkml.org/lkml/2012/11/16/547.
8. Miscellaneous fixes, which were posted to LKML at
https://lkml.org/lkml/2012/10/30/309, along with a late-breaking
change posted at Fri, 16 Nov 2012 11:26:25 -0800 with message-ID
<20121116192625.GA447@linux.vnet.ibm.com>, but which lkml.org
seems to have missed. These are at branch rcu/fixes.
9. Finally, a fix for an lockdep-RCU splat was posted to LKML
at https://lkml.org/lkml/2012/11/7/486. This is at rcu/next. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add the arch symbol prefix (if applicable) to the asm definition of
modsign_certificate_list and modsign_certificate_list_end. This uses the
recently defined SYMBOL_PREFIX which is derived from
CONFIG_SYMBOL_PREFIX.
This fixes the build of module signing on the blackfin and metag
architectures.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Recently, workqueue code has gone through some changes and we found
some bugs related to concurrency management operations happening on
the wrong CPU. When a worker is concurrency managed
(!WORKER_NOT_RUNNIG), it should be bound to its associated cpu and
woken up to that cpu. Add WARN_ON_ONCE() to verify this.
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Return type of work_busy() is unsigned int.
There is return statement returning boolean value, 'false' in work_busy().
It is not problem, because 'false' may be treated '0'.
However, fixing it would make code robust.
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
8376fe22c7 ("workqueue: implement mod_delayed_work[_on]()")
implemented mod_delayed_work[_on]() using the improved
try_to_grab_pending(). The function is later used, among others, to
replace [__]candel_delayed_work() + queue_delayed_work() combinations.
Unfortunately, a delayed_work item w/ zero @delay is handled slightly
differently by mod_delayed_work_on() compared to
queue_delayed_work_on(). The latter skips timer altogether and
directly queues it using queue_work_on() while the former schedules
timer which will expire on the closest tick. This means, when @delay
is zero, that [__]cancel_delayed_work() + queue_delayed_work_on()
makes the target item immediately executable while
mod_delayed_work_on() may induce delay of upto a full tick.
This somewhat subtle difference breaks some of the converted users.
e.g. block queue plugging uses delayed_work for deferred processing
and uses mod_delayed_work_on() when the queue needs to be immediately
unplugged. The above problem manifested as noticeably higher number
of context switches under certain circumstances.
The difference in behavior was caused by missing special case handling
for 0 delay in mod_delayed_work_on() compared to
queue_delayed_work_on(). Joonsoo Kim posted a patch to add it -
("workqueue: optimize mod_delayed_work_on() when @delay == 0")[1].
The patch was queued for 3.8 but it was described as optimization and
I missed that it was a correctness issue.
As both queue_delayed_work_on() and mod_delayed_work_on() use
__queue_delayed_work() for queueing, it seems that the better approach
is to move the 0 delay special handling to the function instead of
duplicating it in mod_delayed_work_on().
Fix the problem by moving 0 delay special case handling from
queue_delayed_work_on() to __queue_delayed_work(). This replaces
Joonsoo's patch.
[1] http://thread.gmane.org/gmane.linux.kernel/1379011/focus=1379012
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Anders Kaseorg <andersk@MIT.EDU>
Reported-and-tested-by: Zlatko Calusic <zlatko.calusic@iskon.hr>
LKML-Reference: <alpine.DEB.2.00.1211280953350.26602@dr-wily.mit.edu>
LKML-Reference: <50A78AA9.5040904@iskon.hr>
Cc: Joonsoo Kim <js1304@gmail.com>
A rescue thread exiting TASK_INTERRUPTIBLE can lead to a task scheduling
off, never to be seen again. In the case where this occurred, an exiting
thread hit reiserfs homebrew conditional resched while holding a mutex,
bringing the box to its knees.
PID: 18105 TASK: ffff8807fd412180 CPU: 5 COMMAND: "kdmflush"
#0 [ffff8808157e7670] schedule at ffffffff8143f489
#1 [ffff8808157e77b8] reiserfs_get_block at ffffffffa038ab2d [reiserfs]
#2 [ffff8808157e79a8] __block_write_begin at ffffffff8117fb14
#3 [ffff8808157e7a98] reiserfs_write_begin at ffffffffa0388695 [reiserfs]
#4 [ffff8808157e7ad8] generic_perform_write at ffffffff810ee9e2
#5 [ffff8808157e7b58] generic_file_buffered_write at ffffffff810eeb41
#6 [ffff8808157e7ba8] __generic_file_aio_write at ffffffff810f1a3a
#7 [ffff8808157e7c58] generic_file_aio_write at ffffffff810f1c88
#8 [ffff8808157e7cc8] do_sync_write at ffffffff8114f850
#9 [ffff8808157e7dd8] do_acct_process at ffffffff810a268f
[exception RIP: kernel_thread_helper]
RIP: ffffffff8144a5c0 RSP: ffff8808157e7f58 RFLAGS: 00000202
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8107af60 RDI: ffff8803ee491d18
RBP: 0000000000000000 R8: 0000000000000000 R9: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Pull perf fixes from Ingo Molnar:
"This is mostly about unbreaking architectures that took the UAPI
changes in the v3.7 cycle, plus misc fixes."
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf kvm: Fix building perf kvm on non x86 arches
perf kvm: Rename perf_kvm to perf_kvm_stat
perf: Make perf build for x86 with UAPI disintegration applied
perf powerpc: Use uapi/unistd.h to fix build error
tools: Pass the target in descend
tools: Honour the O= flag when tool build called from a higher Makefile
tools: Define a Makefile function to do subdir processing
x86: Export asm/{svm.h,vmx.h,perf_regs.h}
perf tools: Fix strbuf_addf() when the buffer needs to grow
perf header: Fix numa topology printing
perf, powerpc: Fix hw breakpoints returning -ENOSPC
cgroup_clear_directory() incorrectly invokes cgroup_rm_file() on each
cftset of the target subsystems, which only removes the first file of
each set. This leaves dangling files after subsystems are removed
from a cgroup root via remount.
Use cgroup_addrm_files() to remove all files of target subsystems.
tj: Move cgroup_addrm_files() prototype decl upwards next to other
global declarations. Commit message updated.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Create a new subsystem that probes on kernel boundaries
to keep track of the transitions between level contexts
with two basic initial contexts: user or kernel.
This is an abstraction of some RCU code that use such tracking
to implement its userspace extended quiescent state.
We need to pull this up from RCU into this new level of indirection
because this tracking is also going to be used to implement an "on
demand" generic virtual cputime accounting. A necessary step to
shutdown the tick while still accounting the cputime.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
[ paulmck: fix whitespace error and email address. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The function rb_check_pages() was added to make sure the ring buffer's
pages were sane. This check is done when the ring buffer size is modified
as well as when the iterator is released (closing the "trace" file),
as that was considered a non fast path and a good place to do a sanity
check.
The problem is that the check does not have any locks around it.
If one process were to read the trace file, and another were to read
the raw binary file, the check could happen while the reader is reading
the file.
The issues with this is that the check requires to clear the HEAD page
before doing the full check and it restores it afterward. But readers
require the HEAD page to exist before it can read the buffer, otherwise
it gives a nasty warning and disables the buffer.
By adding the reader lock around the check, this keeps the race from
happening.
Cc: stable@vger.kernel.org # 3.6
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The function rb_set_head_page() searches the list of ring buffer
pages for a the page that has the HEAD page flag set. If it does
not find it, it will do a WARN_ON(), disable the ring buffer and
return NULL, as this should never happen.
But if this bug happens to happen, not all callers of this function
can handle a NULL pointer being returned from it. That needs to be
fixed.
Cc: stable@vger.kernel.org # 3.0+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If everything goes right, it shouldn't really matter if we are spitting
this warning after css_alloc or css_online. If we fail between then,
there are some ill cases where we would previously see the message and
now we won't (like if the files fail to be created).
I believe it really shouldn't matter: this message is intended in spirit
to be shown when creation succeeds, but with insane settings.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
In the simple irqdomain: don't shout warnings to the user,
there is no point. An informational print is sufficient.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
* pm-cpuidle:
cpuidle: Measure idle state durations with monotonic clock
cpuidle: fix a suspicious RCU usage in menu governor
cpuidle: support multiple drivers
cpuidle: prepare the cpuidle core to handle multiple drivers
cpuidle: move driver checking within the lock section
cpuidle: move driver's refcount to cpuidle
cpuidle: fixup device.h header in cpuidle.h
cpuidle / sysfs: move structure declaration into the sysfs.c file
cpuidle: Get typical recent sleep interval
cpuidle: Set residency to 0 if target Cstate not enter
cpuidle: Quickly notice prediction failure in general case
cpuidle: Quickly notice prediction failure for repeat mode
cpuidle / sysfs: move kobj initialization in the syfs file
cpuidle / sysfs: change function parameter
* acpi-general: (38 commits)
ACPI / thermal: _TMP and _CRT/_HOT/_PSV/_ACx dependency fix
ACPI: drop unnecessary local variable from acpi_system_write_wakeup_device()
ACPI: Fix logging when no pci_irq is allocated
ACPI: Update Dock hotplug error messages
ACPI: Update Container hotplug error messages
ACPI: Update Memory hotplug error messages
ACPI: Update CPU hotplug error messages
ACPI: Add acpi_handle_<level>() interfaces
ACPI: remove use of __devexit
ACPI / PM: Add Sony Vaio VPCEB1S1E to nonvs blacklist.
ACPI / battery: Correct battery capacity values on Thinkpads
Revert "ACPI / x86: Add quirk for "CheckPoint P-20-00" to not use bridge _CRS_ info"
ACPI: create _SUN sysfs file
ACPI / memhotplug: bind the memory device when the driver is being loaded
ACPI / memhotplug: don't allow to eject the memory device if it is being used
ACPI / memhotplug: free memory device if acpi_memory_enable_device() failed
ACPI / memhotplug: fix memory leak when memory device is unbound from acpi_memhotplug
ACPI / memhotplug: deal with eject request in hotplug queue
ACPI / memory-hotplug: add memory offline code to acpi_memory_device_remove()
ACPI / memory-hotplug: call acpi_bus_trim() to remove memory device
...
Conflicts:
include/linux/acpi.h (two additions at the end of the same file)
* pm-qos:
PM / QoS: Handle device PM QoS flags while removing constraints
PM / QoS: Resume device before exposing/hiding PM QoS flags
PM / QoS: Document request manipulation requirement for flags
PM / QoS: Fix a free error in the dev_pm_qos_constraints_destroy()
PM / QoS: Fix the return value of dev_pm_qos_update_request()
PM / ACPI: Take device PM QoS flags into account
PM / Domains: Check device PM QoS flags in pm_genpd_poweroff()
PM / QoS: Make it possible to expose PM QoS device flags to user space
PM / QoS: Introduce PM QoS device flags support
PM / QoS: Prepare struct dev_pm_qos_request for more request types
PM / QoS: Introduce request and constraint data types for PM QoS flags
PM / QoS: Prepare device structure for adding more constraint types
the first one is equal to signal_pt_regs(), the second is never used
(and always NULL, while we are at it).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and get rid of idiotic struct pt_regs * in asm-generic/syscalls.h
prototypes of the same, while we are at it. Eventually we want those
in linux/syscalls.h, of course, but that'll have to wait a bit.
Note that there are *three* variants of sys_clone() order of arguments.
Braindamage galore...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use list_del_init() rather than list_del() to remove events from
cgrp->event_list. No functional change. This is just defensive
coding.
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The cgroup_event_wake() function is called with the wait queue head
locked and it takes cgrp->event_list_lock. However, in cgroup_rmdir()
remove_wait_queue() was being called after taking
cgrp->event_list_lock. Correct the lock ordering by using a temporary
list to obtain the event list to remove from the wait queue.
Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Aaron Durbin <adurbin@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Remove conditional code based on CONFIG_HOTPLUG being false. It's
always on now in preparation of it going away as an option.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove conditional code based on CONFIG_HOTPLUG being false. It's
always on now in preparation of it going away as an option.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The reason for the scaling and monotonicity correction performed
by cputime_adjust() may not be immediately clear to the reviewer.
Add some comments to explain what happens there.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
task_cputime_adjusted() and thread_group_cputime_adjusted()
essentially share the same code. They just don't use the same
source:
* The first function uses the cputime in the task struct and the
previous adjusted snapshot that ensures monotonicity.
* The second adds the cputime of all tasks in the group and the
previous adjusted snapshot of the whole group from the signal
structure.
Just consolidate the common code that does the adjustment. These
functions just need to fetch the values from the appropriate
source.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
We have thread_group_cputime() and thread_group_times(). The naming
doesn't provide enough information about the difference between
these two APIs.
To lower the confusion, rename thread_group_times() to
thread_group_cputime_adjusted(). This name better suggests that
it's a version of thread_group_cputime() that does some stabilization
on the raw cputime values. ie here: scale on top of CFS runtime
stats and bound lower value for monotonicity.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
thread_group_cputime() is a general cputime API that is not only
used by posix cpu timer. Let's move this helper to sched code.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
2243076ad1 ("cgroup: initialize cgrp->allcg_node in
init_cgroup_housekeeping()") initializes cgrp->allcg_node in
init_cgroup_housekeeping(). Then in init_cgroup_root(), we should
call init_cgroup_housekeeping() before adding it to &root->allcg_list;
otherwise, we are initializing an entry already in a list.
Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
As suggested by John, export time data similarly to how its
done by vsyscall support. This allows KVM to retrieve necessary
information to implement vsyscall support in KVM guests.
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Dave Jones reported a bug with futex_lock_pi() that his trinity test
exposed. Sometime between queue_me() and taking the q.lock_ptr, the
lock_ptr became NULL, resulting in a crash.
While futex_wake() is careful to not call wake_futex() on futex_q's with
a pi_state or an rt_waiter (which are either waiting for a
futex_unlock_pi() or a PI futex_requeue()), futex_wake_op() and
futex_requeue() do not perform the same test.
Update futex_wake_op() and futex_requeue() to test for q.pi_state and
q.rt_waiter and abort with -EINVAL if detected. To ensure any future
breakage is caught, add a WARN() to wake_futex() if the same condition
is true.
This fix has seen 3 hours of testing with "trinity -c futex" on an
x86_64 VM with 4 CPUS.
[akpm@linux-foundation.org: tidy up the WARN()]
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Reported-by: Dave Jones <davej@redat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: John Kacur <jkacur@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In get_sample_period(), unsigned long is not enough:
watchdog_thresh * 2 * (NSEC_PER_SEC / 5)
case1:
watchdog_thresh is 10 by default, the sample value will be: 0xEE6B2800
case2:
set watchdog_thresh is 20, the sample value will be: 0x1 DCD6 5000
In case2, we need use u64 to express the sample period. Otherwise,
changing the threshold thru proc often can not be successful.
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
'guarantee' is already removed from cgroup_task_migrate, so remove
the corresponding comments. Some other typos in cgroup are also
changed.
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Assign a unique proc inode to each namespace, and use that
inode number to ensure we only allocate at most one proc
inode for every namespace in proc.
A single proc inode per namespace allows userspace to test
to see if two processes are in the same namespace.
This has been a long requested feature and only blocked because
a naive implementation would put the id in a global space and
would ultimately require having a namespace for the names of
namespaces, making migration and certain virtualization tricks
impossible.
We still don't have per superblock inode numbers for proc, which
appears necessary for application unaware checkpoint/restart and
migrations (if the application is using namespace file descriptors)
but that is now allowd by the design if it becomes important.
I have preallocated the ipc and uts initial proc inode numbers so
their structures can be statically initialized.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
To keep things sane in the context of file descriptor passing derive the
user namespace that uids are mapped into from the opener of the file
instead of from current.
When writing to the maps file the lower user namespace must always
be the parent user namespace, or setting the mapping simply does
not make sense. Enforce that the opener of the file was in
the parent user namespace or the user namespace whose mapping
is being set.
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
- Add CLONE_THREAD to the unshare flags if CLONE_NEWUSER is selected
As changing user namespaces is only valid if all there is only
a single thread.
- Restore the code to add CLONE_VM if CLONE_THREAD is selected and
the code to addCLONE_SIGHAND if CLONE_VM is selected.
Making the constraints in the code clear.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This allows entering a user namespace, and the ability
to store a reference to a user namespace with a bind
mount.
Addition of missing userns_ns_put in userns_install
from Gao feng <gaofeng@cn.fujitsu.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The task_user_ns function hides the fact that it is getting the user
namespace from struct cred on the task. struct cred may go away as
soon as the rcu lock is released. This leads to a race where we
can dereference a stale user namespace pointer.
To make it obvious a struct cred is involved kill task_user_ns.
To kill the race modify the users of task_user_ns to only
reference the user namespace while the rcu lock is held.
Cc: Kees Cook <keescook@chromium.org>
Cc: James Morris <james.l.morris@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Modify create_new_namespaces to explicitly take a user namespace
parameter, instead of implicitly through the task_struct.
This allows an implementation of unshare(CLONE_NEWUSER) where
the new user namespace is not stored onto the current task_struct
until after all of the namespaces are created.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
- Push the permission check from the core setns syscall into
the setns install methods where the user namespace of the
target namespace can be determined, and used in a ns_capable
call.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
If an unprivileged user has the appropriate capabilities in their
current user namespace allow the creation of new namespaces.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
WARN shouldn't be used as a means of communicating failure to a userspace programmer.
Link: http://lkml.kernel.org/r/20120725153908.GA25203@redhat.com
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
It seems that 'ftrace_enabled' flag should not be used inside the tracer
functions. The ftrace core is using this flag for internal purposes, and
the flag wasn't meant to be used in tracers' runtime checks.
stack tracer is the only tracer that abusing the flag. So stop it from
serving as a bad example.
Also, there is a local 'stack_trace_disabled' flag in the stack tracer,
which is never updated; so it can be removed as well.
Link: http://lkml.kernel.org/r/1342637761-9655-1-git-send-email-anton.vorontsov@linaro.org
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
With the introduction of generic cgroup hierarchy iterators, css_id is
being phased out. It was unnecessarily complex, id'ing the wrong
thing (cgroups need IDs, not CSSes) and has other oddities like not
being available at ->css_alloc().
This patch adds cgroup->id, which is a simple per-hierarchy
ida-allocated ID which is assigned before ->css_alloc() and released
after ->css_free().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Currently CGRP_CPUSET_CLONE_CHILDREN triggers ->post_clone(). Now
that clone_children is cpuset specific, there's no reason to have this
rather odd option activation mechanism in cgroup core. cpuset can
check the flag from its ->css_allocate() and take the necessary
action.
Move cpuset_post_clone() logic to the end of cpuset_css_alloc() and
remove cgroup_subsys->post_clone().
Loosely based on Glauber's "generalize post_clone into post_create"
patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Original-patch-by: Glauber Costa <glommer@parallels.com>
Original-patch: <1351686554-22592-2-git-send-email-glommer@parallels.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>
clone_children is only meaningful for cpuset and will stay that way.
Rename the flag to reflect that and update documentation. Also, drop
clone_children() wrapper in cgroup.c. The thin wrapper is used only a
few times and one of them will go away soon.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>
Rename cgroup_subsys css lifetime related callbacks to better describe
what their roles are. Also, update documentation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
There could be cases where controllers want to do initialization
operations which may fail from ->post_create(). This patch makes
->post_create() return -errno to indicate failure and online_css()
relay such failures.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>
cgroup_create() was ignoring failure of cgroupfs files. Update it
such that, if file creation fails, it rolls back by calling
cgroup_destroy_locked() and returns failure.
Note that error out goto labels are renamed. The labels are a bit
confusing but will become better w/ later cgroup operation renames.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
All cgroup directory i_mutexes nest outside cgroup_mutex; however, new
directory creation is a special case. A new cgroup directory is
created while holding cgroup_mutex. Populating the new directory
requires both the new directory's i_mutex and cgroup_mutex. Because
all directory i_mutexes nest outside cgroup_mutex, grabbing both
requires releasing cgroup_mutex first, which isn't a good idea as the
new cgroup isn't yet ready to be manipulated by other cgroup
opreations.
This is worked around by grabbing the new directory's i_mutex while
holding cgroup_mutex before making it visible. As there's no other
user at that point, grabbing the i_mutex under cgroup_mutex can't lead
to deadlock.
cgroup_create_file() was using I_MUTEX_CHILD to tell lockdep not to
worry about the reverse locking order; however, this creates pseudo
locking dependency cgroup_mutex -> I_MUTEX_CHILD, which isn't true -
all directory i_mutexes are still nested outside cgroup_mutex. This
pseudo locking dependency can lead to spurious lockdep warnings.
Use mutex_trylock() instead. This will always succeed and lockdep
doesn't create any locking dependency for it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Now that cgroup_unload_subsys() can tell whether the root css is
online or not, we can safely call cgroup_unload_subsys() after idr
init failure in cgroup_load_subsys().
Replace the manual unrolling and invoke cgroup_unload_subsys() on
failure. This drops cgroup_mutex inbetween but should be safe as the
subsystem will fail try_module_get() and thus can't be mounted
inbetween. As this means that cgroup_unload_subsys() can be called
before css_sets are rehashed, remove BUG_ON() on %NULL
css_set->subsys[] from cgroup_unload_subsys().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
New helpers on/offline_css() respectively wrap ->post_create() and
->pre_destroy() invocations. online_css() sets CSS_ONLINE after
->post_create() is complete and offline_css() invokes ->pre_destroy()
iff CSS_ONLINE is set and clears it while also handling the temporary
dropping of cgroup_mutex.
This patch doesn't introduce any behavior change at the moment but
will be used to improve cgroup_create() failure path and allow
->post_create() to fail.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Separate out cgroup_destroy_locked() from cgroup_destroy(). This will
be later used in cgroup_create() failure path.
While at it, add lockdep asserts on i_mutex and cgroup_mutex, and move
@d and @parent assignments to their declarations.
This patch doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
* If idr init fails, cgroup_load_subsys() cleared dummytop->subsys[]
before calilng ->destroy() making CSS inaccessible to the callback,
and didn't unlink ss->sibling. As no modular controller uses
->use_id, this doesn't cause any actual problems.
* cgroup_unload_subsys() was forgetting to free idr, call
->pre_destroy() and clear ->active. As there currently is no
modular controller which uses ->use_id, ->pre_destroy() or ->active,
this doesn't cause any actual problems.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Make cgroup_init_subsys() grab cgroup_mutex while initializing a
subsystem so that all helpers and callbacks are called under the
context they expect. This isn't strictly necessary as
cgroup_init_subsys() doesn't race with anybody but will allow adding
lockdep assertions.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Consistently use @css and @dummytop in these two functions instead of
referring to them indirectly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Currently, CSS_* flags are defined as bit positions and manipulated
using atomic bitops. There's no reason to use atomic bitops for them
and bit positions are clunkier to deal with than bit masks. Make
CSS_* bit masks instead and use the usual C bitwise operators to
access them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup->dentry is marked and used as a RCU pointer; however, it isn't
one - the final dentry put doesn't go through call_rcu(). cgroup and
dentry share the same RCU freeing rule via synchronize_rcu() in
cgroup_diput() (kfree_rcu() used on cgrp is unnecessary). If cgrp is
accessible under RCU read lock, so is its dentry and dereferencing
cgrp->dentry doesn't need any further RCU protection or annotation.
While not being accurate, before the previous patch, the RCU accessors
served a purpose as memory barriers - cgroup->dentry used to be
assigned after the cgroup was made visible to cgroup_path(), so the
assignment and dereferencing in cgroup_path() needed the memory
barrier pair. Now that list_add_tail_rcu() happens after
cgroup->dentry is assigned, this no longer is necessary.
Remove the now unnecessary and misleading RCU annotations from
cgroup->dentry. To make up for the removal of rcu_dereference_check()
in cgroup_path(), add an explicit rcu_lockdep_assert(), which asserts
the dereference rule of @cgrp, not cgrp->dentry.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
While creating a new cgroup, cgroup_create() links the newly allocated
cgroup into various places before trying to create its directory.
Because cgroup life-cycle is tied to the vfs objects, this makes it
impossible to use cgroup_rmdir() for rolling back creation - the
removal logic depends on having full vfs objects.
This patch moves directory creation above linking and collect linking
operations to one place. This allows directory creation failure to
share error exit path with css allocation failures and any failure
sites afterwards (to be added later) can use cgroup_rmdir() logic to
undo creation.
Note that this also makes the memory barriers around cgroup->dentry,
which currently is misleadingly using RCU operations, unnecessary.
This will be handled in the next patch.
While at it, locking BUG_ON() on i_mutex is converted to
lockdep_assert_held().
v2: Patch originally removed %NULL dentry check in cgroup_path();
however, Li pointed out that this patch doesn't make it
unnecessary as ->create() may call cgroup_path(). Drop the
change for now.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
The operation order of cgroup creation is about to change and
cgroup_create_dir() is more of a hindrance than a proper abstraction.
Open-code it by moving the parent nlink adjustment next to self nlink
adjustment in cgroup_create_file() and the rest to cgroup_create().
This patch doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Not strictly necessary but it's annoying to have uninitialized
list_head around.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
vtime_account() is only called from irq entry. irqs
are always disabled at this point so we can safely
remove the irq disabling guards on that function.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
On ia64 and powerpc, vtime context switch only consists
in flushing system and user pending time, plus a few
arch housekeeping.
Consolidate that into a generic implementation. s390 is
a special case because pending user and system time accounting
there is hard to dissociate. So it's keeping its own implementation.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Prepending irq-unsafe vtime APIs with underscores was actually
a bad idea as the result is a big mess in the API namespace that
is even waiting to be further extended. Also these helpers
are always called from irq safe callers except kvm. Just
provide a vtime_account_system_irqsafe() for this specific
case so that we can remove the underscore prefix on other
vtime functions.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Now that we have been through every permission check in the kernel
having uid == 0 and gid == 0 in your local user namespace no
longer adds any special privileges. Even having a full set
of caps in your local user namespace is safe because capabilies
are relative to your local user namespace, and do not confer
unexpected privileges.
Over the long term this should allow much more of the kernels
functionality to be safely used by non-root users. Functionality
like unsharing the mount namespace that is only unsafe because
it can fool applications whose privileges are raised when they
are executed. Since those applications have no privileges in
a user namespaces it becomes safe to spoof and confuse those
applications all you want.
Those capabilities will still need to be enabled carefully because
we may still need things like rlimits on the number of unprivileged
mounts but that is to avoid DOS attacks not to avoid fooling root
owned processes.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This will allow for support for unprivileged mounts in a new user namespace.
Acked-by: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Unsharing of the pid namespace unlike unsharing of other namespaces
does not take affect immediately. Instead it affects the children
created with fork and clone. The first of these children becomes the init
process of the new pid namespace, the rest become oddball children
of pid 0. From the point of view of the new pid namespace the process
that created it is pid 0, as it's pid does not map.
A couple of different semantics were considered but this one was
settled on because it is easy to implement and it is usable from
pam modules. The core reasons for the existence of unshare.
I took a survey of the callers of pam modules and the following
appears to be a representative sample of their logic.
{
setup stuff include pam
child = fork();
if (!child) {
setuid()
exec /bin/bash
}
waitpid(child);
pam and other cleanup
}
As you can see there is a fork to create the unprivileged user
space process. Which means that the unprivileged user space
process will appear as pid 1 in the new pid namespace. Further
most login processes do not cope with extraneous children which
means shifting the duty of reaping extraneous child process to
the creator of those extraneous children makes the system more
comprehensible.
The practical reason for this set of pid namespace semantics is
that it is simple to implement and verify they work correctly.
Whereas an implementation that requres changing the struct
pid on a process comes with a lot more races and pain. Not
the least of which is that glibc caches getpid().
These semantics are implemented by having two notions
of the pid namespace of a proces. There is task_active_pid_ns
which is the pid namspace the process was created with
and the pid namespace that all pids are presented to
that process in. The task_active_pid_ns is stored
in the struct pid of the task.
Then there is the pid namespace that will be used for children
that pid namespace is stored in task->nsproxy->pid_ns.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Instead of setting child_reaper and SIGNAL_UNKILLABLE one way
for the system init process, and another way for pid namespace
init processes test pid->nr == 1 and use the same code for both.
For the global init this results in SIGNAL_UNKILLABLE being set
much earlier in the initialization process.
This is a small cleanup and it paves the way for allowing unshare and
enter of the pid namespace as that path like our global init also will
not set CLONE_NEWPID.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
- Pid namespaces are designed to be inescapable so verify that the
passed in pid namespace is a child of the currently active
pid namespace or the currently active pid namespace itself.
Allowing the currently active pid namespace is important so
the effects of an earlier setns can be cancelled.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
task_active_pid_ns(current) != current->ns_proxy->pid_ns will
soon be allowed to support unshare and setns.
The definition of creating a child pid namespace when
task_active_pid_ns(current) != current->ns_proxy->pid_ns could be that
we create a child pid namespace of current->ns_proxy->pid_ns. However
that leads to strange cases like trying to have a single process be
init in multiple pid namespaces, which is racy and hard to think
about.
The definition of creating a child pid namespace when
task_active_pid_ns(current) != current->ns_proxy->pid_ns could be that
we create a child pid namespace of task_active_pid_ns(current). While
that seems less racy it does not provide any utility.
Therefore define the semantics of creating a child pid namespace when
task_active_pid_ns(current) != current->ns_proxy->pid_ns to be that the
pid namespace creation fails. That is easy to implement and easy
to think about.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Looking at pid_ns->nr_hashed is a bit simpler and it works for
disjoint process trees that an unshare or a join of a pid_namespace
may create.
Acked-by: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Set nr_hashed to -1 just before we schedule the work to cleanup proc.
Test nr_hashed just before we hash a new pid and if nr_hashed is < 0
fail.
This guaranteees that processes never enter a pid namespaces after we
have cleaned up the state to support processes in a pid namespace.
Currently sending SIGKILL to all of the process in a pid namespace as
init exists gives us this guarantee but we need something a little
stronger to support unsharing and joining a pid namespace.
Acked-by: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Track the number of pids in the proc hash table. When the number of
pids goes to 0 schedule work to unmount the kernel mount of proc.
Move the mount of proc into alloc_pid when we allocate the pid for
init.
Remove the surprising calls of pid_ns_release proc in fork and
proc_flush_task. Those code paths really shouldn't know about proc
namespace implementation details and people have demonstrated several
times that finding and understanding those code paths is difficult and
non-obvious.
Because of the call path detach pid is alwasy called with the
rtnl_lock held free_pid is not allowed to sleep, so the work to
unmounting proc is moved to a work queue. This has the side benefit
of not blocking the entire world waiting for the unnecessary
rcu_barrier in deactivate_locked_super.
In the process of making the code clear and obvious this fixes a bug
reported by Gao feng <gaofeng@cn.fujitsu.com> where we would leak a
mount of proc during clone(CLONE_NEWPID|CLONE_NEWNET) if copy_pid_ns
succeeded and copy_net_ns failed.
Acked-by: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The expressions tsk->nsproxy->pid_ns and task_active_pid_ns
aka ns_of_pid(task_pid(tsk)) should have the same number of
cache line misses with the practical difference that
ns_of_pid(task_pid(tsk)) is released later in a processes life.
Furthermore by using task_active_pid_ns it becomes trivial
to write an unshare implementation for the the pid namespace.
So I have used task_active_pid_ns everywhere I can.
In fork since the pid has not yet been attached to the
process I use ns_of_pid, to achieve the same effect.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
- Capture the the user namespace that creates the pid namespace
- Use that user namespace to test if it is ok to write to
/proc/sys/kernel/ns_last_pid.
Zhao Hongjiang <zhaohongjiang@huawei.com> noticed I was missing a put_user_ns
in when destroying a pid_ns. I have foloded his patch into this one
so that bisects will work properly.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The user namespace which creates a new network namespace owns that
namespace and all resources created in it. This way we can target
capability checks for privileged operations against network resources to
the user_ns which created the network namespace in which the resource
lives. Privilege to the user namespace which owns the network
namespace, or any parent user namespace thereof, provides the same
privilege to the network resource.
This patch is reworked from a version originally by
Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
The user namespace which creates a new network namespace owns that
namespace and all resources created in it. This way we can target
capability checks for privileged operations against network resources to
the user_ns which created the network namespace in which the resource
lives. Privilege to the user namespace which owns the network
namespace, or any parent user namespace thereof, provides the same
privilege to the network resource.
This patch is reworked from a version originally by
Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
klogd is woken up asynchronously from the tick in order
to do it safely.
However if printk is called when the tick is stopped, the reader
won't be woken up until the next interrupt, which might not fire
for a while. As a result, the user may miss some message.
To fix this, lets implement the printk tick using a lazy irq work.
This subsystem takes care of the timer tick state and can
fix up accordingly.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
On irq work initialization, let the user choose to define it
as "lazy" or not. "Lazy" means that we don't want to send
an IPI (provided the arch can anyway) when we enqueue this
work but we rather prefer to wait for the next timer tick
to execute our work if possible.
This is going to be a benefit for non-urgent enqueuers
(like printk in the future) that may prefer not to raise
an IPI storm in case of frequent enqueuing on short periods
of time.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
If we are in nohz and there's still irq_work to be done when the idle
task is about to go offline, give a nasty warning. Everything should
have been flushed from the CPU_DYING notifier already. Further attempts
to enqueue an irq_work are buggy because irqs are disabled by
__cpu_disable(). The best we can do is to report the issue to the user.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
In order not to offline a CPU with pending irq works, flush the
queue from CPU_DYING. The notifier is called by stop_machine on
the CPU that is going down. The code will not be called from irq context
(so things like get_irq_regs() wont work) but I'm not sure what the
requirements are for irq_work in that regard (Peter?). But irqs are
disabled and the CPU is about to go offline. Might as well flush the work.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Don't stop the tick if we have pending irq works on the
queue, otherwise if the arch can't raise self-IPIs, we may not
find an opportunity to execute the pending works for a while.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
We need some quick way to check if the CPU has stopped
its tick. This will be useful to implement the printk tick
using the irq work subsystem.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Currently, callback invocations from callback-free CPUs are accounted to
the CPU that registered the callback, but using the same field that is
used for normal callbacks. This makes it impossible to determine from
debugfs output whether callbacks are in fact being diverted. This commit
therefore adds a separate ->n_nocbs_invoked field in the rcu_data structure
in which diverted callback invocations are counted. RCU's debugfs tracing
still displays normal callback invocations using ci=, but displayed
diverted callbacks with nci=.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
RCU callback execution can add significant OS jitter and also can
degrade both scheduling latency and, in asymmetric multiprocessors,
energy efficiency. This commit therefore adds the ability for selected
CPUs ("rcu_nocbs=" boot parameter) to have their callbacks offloaded
to kthreads. If the "rcu_nocb_poll" boot parameter is also specified,
these kthreads will do polling, removing the need for the offloaded
CPUs to do wakeups. At least one CPU must be doing normal callback
processing: currently CPU 0 cannot be selected as a no-CBs CPU.
In addition, attempts to offline the last normal-CBs CPU will fail.
This feature was inspired by Jim Houston's and Joe Korty's JRCU, and
this commit includes fixes to problems located by Fengguang Wu's
kbuild test robot.
[ paulmck: Added gfp.h include file as suggested by Fengguang Wu. ]
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
urgent.2012.10.27a: Fix for RCU user-mode transition (already in -tip).
doc.2012.11.08a: Documentation updates, most notably codifying the
memory-barrier guarantees inherent to grace periods.
fixes.2012.11.13a: Miscellaneous fixes.
srcu.2012.10.27a: Allow statically allocated and initialized srcu_struct
structures (courtesy of Lai Jiangshan).
stall.2012.11.13a: Add more diagnostic information to RCU CPU stall
warnings, also decrease from 60 seconds to 21 seconds.
hotplug.2012.11.08a: Minor updates to CPU hotplug handling.
tracing.2012.11.08a: Improved debugfs tracing, courtesy of Michael Wang.
idle.2012.10.24a: Updates to RCU idle/adaptive-idle handling, including
a boot parameter that maps normal grace periods to expedited.
Resolved conflict in kernel/rcutree.c due to side-by-side change.
This was always racy, but 268720903f
"uprobes: Rework register_for_each_vma() to make it O(n)" should be
blamed anyway, it made everything worse and I didn't notice.
register/unregister call build_map_info() and then do install/remove
breakpoint for every mm which mmaps inode/offset. This can obviously
race with fork()->dup_mmap() in between and we can miss the child.
uprobe_register() could be easily fixed but unregister is much worse,
the new mm inherits "int3" from parent and there is no way to detect
this if uprobe goes away.
So this patch simply adds percpu_down_read/up_read around dup_mmap(),
and percpu_down_write/up_write into register_for_each_vma().
This adds 2 new hooks into dup_mmap() but we can kill uprobe_dup_mmap()
and fold it into uprobe_end_dup_mmap().
Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Trace buffer size is now per-cpu, so that there are the following two
patterns in resizing of buffers.
(1) resize per-cpu buffers to same given size
(2) resize per-cpu buffers to another trace_array's buffer size
for each CPU (such as preparing the max_tr which is equivalent
to the global_trace's size)
__tracing_resize_ring_buffer() can be used for (1), and had
implemented (2) inside it for resetting the global_trace to the
original size.
(2) was also implemented in another place. So this patch assembles
them in a new function - resize_buffer_duplicate_size().
Link: http://lkml.kernel.org/r/20121017025616.2627.91226.stgit@falsita
Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There is a typo here where '&' is used instead of '|' and it turns the
statement into a noop. The original code is equivalent to:
iter->flags &= ~((1 << 2) & (1 << 4));
Link: http://lkml.kernel.org/r/20120609161027.GD6488@elgon.mountain
Cc: stable@vger.kernel.org # all of them
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Since the software suspend extents are organized in an rbtree, use rb_entry
instead of container_of, as it is semantically more appropriate in order to
get a node as it is iterated.
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Replace strict_strtoul() with kstrtoul() in pm_async_store() and
pm_qos_power_write().
[rjw: Modified subject and changelog.]
Signed-off-by: Daniel Walter <sahne@0x90.at>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The prediction for future is difficult and when the cpuidle governor prediction
fails and govenor possibly choose the shallower C-state than it should. How to
quickly notice and find the failure becomes important for power saving.
cpuidle menu governor has a method to predict the repeat pattern if there are 8
C-states residency which are continuous and the same or very close, so it will
predict the next C-states residency will keep same residency time.
There is a real case that turbostat utility (tools/power/x86/turbostat)
at kernel 3.3 or early. turbostat utility will read 10 registers one by one at
Sandybridge, so it will generate 10 IPIs to wake up idle CPUs. So cpuidle menu
governor will predict it is repeat mode and there is another IPI wake up idle
CPU soon, so it keeps idle CPU stay at C1 state even though CPU is totally
idle. However, in the turbostat, following 10 registers reading is sleep 5
seconds by default, so the idle CPU will keep at C1 for a long time though it is
idle until break event occurs.
In a idle Sandybridge system, run "./turbostat -v", we will notice that deep
C-state dangles between "70% ~ 99%". After patched the kernel, we will notice
deep C-state stays at >99.98%.
In the patch, a timer is added when menu governor detects a repeat mode and
choose a shallow C-state. The timer is set to a time out value that greater
than predicted time, and we conclude repeat mode prediction failure if timer is
triggered. When repeat mode happens as expected, the timer is not triggered
and CPU waken up from C-states and it will cancel the timer initiatively.
When repeat mode does not happen, the timer will be time out and menu governor
will quickly notice that the repeat mode prediction fails and then re-evaluates
deeper C-states possibility.
Below is another case which will clearly show the patch much benefit:
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <sys/time.h>
#include <time.h>
#include <pthread.h>
volatile int * shutdown;
volatile long * count;
int delay = 20;
int loop = 8;
void usage(void)
{
fprintf(stderr,
"Usage: idle_predict [options]\n"
" --help -h Print this help\n"
" --thread -n Thread number\n"
" --loop -l Loop times in shallow Cstate\n"
" --delay -t Sleep time (uS)in shallow Cstate\n");
}
void *simple_loop() {
int idle_num = 1;
while (!(*shutdown)) {
*count = *count + 1;
if (idle_num % loop)
usleep(delay);
else {
/* sleep 1 second */
usleep(1000000);
idle_num = 0;
}
idle_num++;
}
}
static void sighand(int sig)
{
*shutdown = 1;
}
int main(int argc, char *argv[])
{
sigset_t sigset;
int signum = SIGALRM;
int i, c, er = 0, thread_num = 8;
pthread_t pt[1024];
static char optstr[] = "n:l:t:h:";
while ((c = getopt(argc, argv, optstr)) != EOF)
switch (c) {
case 'n':
thread_num = atoi(optarg);
break;
case 'l':
loop = atoi(optarg);
break;
case 't':
delay = atoi(optarg);
break;
case 'h':
default:
usage();
exit(1);
}
printf("thread=%d,loop=%d,delay=%d\n",thread_num,loop,delay);
count = malloc(sizeof(long));
shutdown = malloc(sizeof(int));
*count = 0;
*shutdown = 0;
sigemptyset(&sigset);
sigaddset(&sigset, signum);
sigprocmask (SIG_BLOCK, &sigset, NULL);
signal(SIGINT, sighand);
signal(SIGTERM, sighand);
for(i = 0; i < thread_num ; i++)
pthread_create(&pt[i], NULL, simple_loop, NULL);
for (i = 0; i < thread_num; i++)
pthread_join(pt[i], NULL);
exit(0);
}
Get powertop V2 from git://github.com/fenrus75/powertop, build powertop.
After build the above test application, then run it.
Test plaform can be Intel Sandybridge or other recent platforms.
#./idle_predict -l 10 &
#./powertop
We will find that deep C-state will dangle between 40%~100% and much time spent
on C1 state. It is because menu governor wrongly predict that repeat mode
is kept, so it will choose the C1 shallow C-state even though it has chance to
sleep 1 second in deep C-state.
While after patched the kernel, we find that deep C-state will keep >99.6%.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Even if acpi_processor_handle_eject() offlines cpu, there is a chance
to online the cpu after that. So the patch closes the window by using
get/put_online_cpus().
Why does the patch change _cpu_up() logic?
The patch cares the race of hot-remove cpu and _cpu_up(). If the patch
does not change it, there is the following race.
hot-remove cpu | _cpu_up()
------------------------------------- ------------------------------------
call acpi_processor_handle_eject() |
call cpu_down() |
call get_online_cpus() |
| call cpu_hotplug_begin() and stop here
call arch_unregister_cpu() |
call acpi_unmap_lsapic() |
call put_online_cpus() |
| start and continue _cpu_up()
return acpi_processor_remove() |
continue hot-remove the cpu |
So _cpu_up() can continue to itself. And hot-remove cpu can also continue
itself. If the patch changes _cpu_up() logic, the race disappears as below:
hot-remove cpu | _cpu_up()
-----------------------------------------------------------------------
call acpi_processor_handle_eject() |
call cpu_down() |
call get_online_cpus() |
| call cpu_hotplug_begin() and stop here
call arch_unregister_cpu() |
call acpi_unmap_lsapic() |
cpu's cpu_present is set |
to false by set_cpu_present()|
call put_online_cpus() |
| start _cpu_up()
| check cpu_present() and return -EINVAL
return acpi_processor_remove() |
continue hot-remove the cpu |
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpu_hotplug_pm_callback should have higher priority than
bsp_pm_callback which depends on cpu_hotplug_pm_callback to disable cpu hotplug
to avoid race during bsp online checking.
This is to hightlight the priorities between the two callbacks in case people
may overlook the order.
Ideally the priorities should be defined in macro/enum instead of fixed values.
To do that, a seperate patchset may be pushed which will touch serveral other
generic files and is out of scope of this patchset.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1352835171-3958-7-git-send-email-fenghua.yu@intel.com
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Flush the cache so that the instructions written to the XOL area are
visible.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Work claiming wants to be SMP-safe.
And by the time we try to claim a work, if it is already executing
concurrently on another CPU, we want to succeed the claiming and queue
the work again because the other CPU may have missed the data we wanted
to handle in our work if it's about to complete there.
This scenario is summarized below:
CPU 1 CPU 2
----- -----
(flags = 0)
cmpxchg(flags, 0, IRQ_WORK_FLAGS)
(flags = 3)
[...]
xchg(flags, IRQ_WORK_BUSY)
(flags = 2)
func()
if (flags & IRQ_WORK_PENDING)
(not true)
cmpxchg(flags, flags, IRQ_WORK_FLAGS)
(flags = 3)
[...]
cmpxchg(flags, IRQ_WORK_BUSY, 0);
(fail, pending on CPU 2)
This state machine is synchronized using [cmp]xchg() on the flags.
As such, the early IRQ_WORK_PENDING check in CPU 2 above is racy.
By the time we check it, we may be dealing with a stale value because
we aren't using an atomic accessor. As a result, CPU 2 may "see"
that the work is still pending on another CPU while it may be
actually completing the work function exection already, leaving
our data unprocessed.
To fix this, we start by speculating about the value we wish to be
in the work->flags but we only make any conclusion after the value
returned by the cmpxchg() call that either claims the work or let
the current owner handle the pending work for us.
Changelog-heavily-inspired-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Anish Kumar <anish198519851985@gmail.com>
The IRQ_WORK_BUSY flag is set right before we execute the
work. Once this flag value is set, the work enters a
claimable state again.
So if we have specific data to compute in our work, we ensure it's
either handled by another CPU or locally by enqueuing the work again.
This state machine is guanranteed by atomic operations on the flags.
So when we set IRQ_WORK_BUSY without using an xchg-like operation,
we break this guarantee as in the following summarized scenario:
CPU 1 CPU 2
----- -----
(flags = 0)
old_flags = flags;
(flags = 0)
cmpxchg(flags, old_flags,
old_flags | IRQ_WORK_FLAGS)
(flags = 3)
[...]
flags = IRQ_WORK_BUSY
(flags = 2)
func()
(sees flags = 3)
cmpxchg(flags, old_flags,
old_flags | IRQ_WORK_FLAGS)
(give up)
cmpxchg(flags, 2, 0);
(flags = 0)
CPU 1 claims a work and executes it, so it sets IRQ_WORK_BUSY and
the work is again in a claimable state. Now CPU 2 has new data to process
and try to claim that work but it may see a stale value of the flags
and think the work is still pending somewhere that will handle our data.
This is because CPU 1 doesn't set IRQ_WORK_BUSY atomically.
As a result, the data expected to be handle by CPU 2 won't get handled.
To fix this, use xchg() to set IRQ_WORK_BUSY, this way we ensure the CPU 2
will see the correct value with cmpxchg() using the expected ordering.
Changelog-heavily-inspired-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Anish Kumar <anish198519851985@gmail.com>
The rcu_is_cpu_rrupt_from_idle() needs to allow for one interrupt level
from the idle loop, but TINY_RCU checks for a call from the idle loop
itself. This commit fixes this issue.
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit explicitly states the memory-ordering properties of the
RCU grace-period primitives. Although these properties were in some
sense implied by the fundmental property of RCU ("a grace period must
wait for all pre-existing RCU read-side critical sections to complete"),
stating it explicitly will be a great labor-saving device.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Several new rcutorture module parameters have been added, but are not
printed to the console at the beginning and end of tests, which makes
it difficult to reproduce a prior test. This commit therefore adds
these new module parameters to the list printed at the beginning and
the end of the tests.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Commit 29c00b4a1d (rcu: Add event-tracing for RCU callback
invocation) added a regression in rcu_do_batch()
Under stress, RCU is supposed to allow to process all items in queue,
instead of a batch of 10 items (blimit), but an integer overflow makes
the effective limit being 1. So, unless there is frequent idle periods
(during which RCU ignores batch limits), RCU can be forced into a
state where it cannot keep up with the callback-generation rate,
eventually resulting in OOM.
This commit therefore converts a few variables in rcu_do_batch() from
int to long to fix this problem, along with the module parameters
controlling the batch limits.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # 3.2 +
Show raw time stamp values for stats per cpu if you choose counter or tsc mode
for trace_clock. Although a unit of tracing time stamp is nsec in local or global mode,
the units in counter and TSC mode are tracing counter and cycles respectively.
Link: http://lkml.kernel.org/r/1352837903-32191-3-git-send-email-dhsharp@google.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: David Sharp <dhsharp@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In order to promote interoperability between userspace tracers and ftrace,
add a trace_clock that reports raw TSC values which will then be recorded
in the ring buffer. Userspace tracers that also record TSCs are then on
exactly the same time base as the kernel and events can be unambiguously
interlaced.
Tested: Enabled a tracepoint and the "tsc" trace_clock and saw very large
timestamp values.
v2:
Move arch-specific bits out of generic code.
v3:
Rename "x86-tsc", cleanups
v7:
Generic arch bits in Kbuild.
Google-Bug-Id: 6980623
Link: http://lkml.kernel.org/r/1352837903-32191-1-git-send-email-dhsharp@google.com
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Signed-off-by: David Sharp <dhsharp@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Now that timekeeping is protected by its own locks, rename
the xtime_lock to jifffies_lock to better describe what it
protects.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Commit f1b8274 ("clocksource: Cleanup clocksource selection") removed all
external references to clocksource_jiffies so there is no need to have the
symbol globally visible.
Fixes the following sparse warning:
CHECK kernel/time/jiffies.c kernel/time/jiffies.c:61:20: warning: symbol 'clocksource_jiffies' was not declared. Should it be static?
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Pull futex fix from Thomas Gleixner:
"Single fix for a long standing futex race when taking over a futex
whose owner died. You can end up with two owners, which violates
quite some rules."
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Handle futex_pi OWNER_DIED take over correctly
Sankara reported that the genirq core code fails to adjust the
affinity of an interrupt thread in several cases:
1) On request/setup_irq() the call to setup_affinity() happens before
the new action is registered, so the new thread is not notified.
2) For secondary shared interrupts nothing notifies the new thread to
change its affinity.
3) Interrupts which have the IRQ_NO_BALANCE flag set are not moving
the thread either.
Fix this by setting the thread affinity flag right on thread creation
time. This ensures that under all circumstances the thread moves to
the right place. Requires a check in irq_thread_check_affinity for an
existing affinity mask (CONFIG_CPU_MASK_OFFSTACK=y)
Reported-and-tested-by: Sankara Muthukrishnan <sankara.m@gmail.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1209041738200.2754@ionos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Conflicts:
drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
Minor conflict between the BCM_CNIC define removal in net-next
and a bug fix added to net. Based upon a conflict resolution
patch posted by Stephen Rothwell.
Signed-off-by: David S. Miller <davem@davemloft.net>
Up until now, cgroup_freezer didn't implement hierarchy properly.
cgroups could be arranged in hierarchy but it didn't make any
difference in how each cgroup_freezer behaved. They all operated
separately.
This patch implements proper hierarchy support. If a cgroup is
frozen, all its descendants are frozen. A cgroup is thawed iff it and
all its ancestors are THAWED. freezer.self_freezing shows the current
freezing state for the cgroup itself. freezer.parent_freezing shows
whether the cgroup is freezing because any of its ancestors is
freezing.
freezer_post_create() locks the parent and new cgroup and inherits the
parent's state and freezer_change_state() applies new state top-down
using cgroup_for_each_descendant_pre() which guarantees that no child
can escape its parent's state. update_if_frozen() uses
cgroup_for_each_descendant_post() to propagate frozen states
bottom-up.
Synchronization could be coarser and easier by using a single mutex to
protect all hierarchy operations. Finer grained approach was used
because it wasn't too difficult for cgroup_freezer and I think it's
beneficial to have an example implementation and cgroup_freezer is
rather simple and can serve a good one.
As this makes cgroup_freezer properly hierarchical,
freezer_subsys.broken_hierarchy marking is removed.
Note that this patch changes userland visible behavior - freezing a
cgroup now freezes all its descendants too. This behavior change is
intended and has been warned via .broken_hierarchy.
v2: Michal spotted a bug in freezer_change_state() - descendants were
inheriting from the wrong ancestor. Fixed.
v3: Documentation/cgroups/freezer-subsystem.txt updated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
A cgroup is online and visible to iteration between ->post_create()
and ->pre_destroy(). This patch introduces CGROUP_FREEZER_ONLINE and
toggles it from the newly added freezer_post_create() and
freezer_pre_destroy() while holding freezer->lock such that a
cgroup_freezer can be reilably distinguished to be online. This will
be used by full hierarchy support.
ONLINE test is added to freezer_apply_state() but it currently doesn't
make any difference as freezer_write() can only be called for an
online cgroup.
Adjusting system_freezing_cnt on destruction is moved from
freezer_destroy() to the new freezer_pre_destroy() for consistency.
This patch doesn't introduce any noticeable behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Introduce FREEZING_SELF and FREEZING_PARENT and make FREEZING OR of
the two flags. This is to prepare for full hierarchy support.
freezer_apply_date() is updated such that it can handle setting and
clearing of both flags. The two flags are also exposed to userland
via read-only files self_freezing and parent_freezing.
Other than the added cgroupfs files, this patch doesn't introduce any
behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
freezer->state was an enum value - one of THAWED, FREEZING and FROZEN.
As the scheduled full hierarchy support requires more than one
freezing condition, switch it to mask of flags. If FREEZING is not
set, it's thawed. FREEZING is set if freezing or frozen. If frozen,
both FREEZING and FROZEN are set. Now that tasks can be attached to
an already frozen cgroup, this also makes freezing condition checks
more natural.
This patch doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
* Make freezer_change_state() take bool @freeze instead of enum
freezer_state.
* Separate out freezer_apply_state() out of freezer_change_state().
This makes freezer_change_state() a rather silly thin wrapper. It
will be filled with hierarchy handling later on.
This patch doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
* Clean-up indentation and line-breaks. Drop the invalid comment
about freezer->lock.
* Make all internal functions take @freezer instead of both @cgroup
and @freezer.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Currently, cgroup doesn't provide any generic helper for walking a
given cgroup's children or descendants. This patch adds the following
three macros.
* cgroup_for_each_child() - walk immediate children of a cgroup.
* cgroup_for_each_descendant_pre() - visit all descendants of a cgroup
in pre-order tree traversal.
* cgroup_for_each_descendant_post() - visit all descendants of a
cgroup in post-order tree traversal.
All three only require the user to hold RCU read lock during
traversal. Verifying that each iterated cgroup is online is the
responsibility of the user. When used with proper synchronization,
cgroup_for_each_descendant_pre() can be used to propagate state
updates to descendants in reliable way. See comments for details.
v2: s/config/state/ in commit message and comments per Michal. More
documentation on synchronization rules.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujisu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Use RCU safe list operations for cgroup->children. This will be used
to implement cgroup children / descendant walking which can be used by
controllers.
Note that cgroup_create() now puts a new cgroup at the end of the
->children list instead of head. This isn't strictly necessary but is
done so that the iteration order is more conventional.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Currently, there's no way for a controller to find out whether a new
cgroup finished all ->create() allocatinos successfully and is
considered "live" by cgroup.
This becomes a problem later when we add generic descendants walking
to cgroup which can be used by controllers as controllers don't have a
synchronization point where it can synchronize against new cgroups
appearing in such walks.
This patch adds ->post_create(). It's called after all ->create()
succeeded and the cgroup is linked into the generic cgroup hierarchy.
This plays the counterpart of ->pre_destroy().
When used in combination with the to-be-added generic descendant
iterators, ->post_create() can be used to implement reliable state
inheritance. It will be explained with the descendant iterators.
v2: Added a paragraph about its future use w/ descendant iterators per
Michal.
v3: Forgot to add ->post_create() invocation to cgroup_load_subsys().
Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>
This commit adds a per-RCU-flavor "rcuexp" file that dumps out
statistics for synchonize_sched_expedited().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit removes the old debugfs interfaces, so that the new
directory-per-RCU-flavor versions remain. Because the RCU flavor is
given by the directory name, there is no need to print it out, so remove
the name from the printout.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch add new 'rcuhier' to each flavor's folder, now we could use:
'cat /debugfs/rcu/rsp/rcuhier'
to get the selected rsp info.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch add new 'rcugp' to each flavor's folder, now we could use:
'cat /debugfs/rcu/rsp/rcugp'
to get the selected rsp info.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch add new 'rcuboost' to each flavor's folder, now we could use:
'cat /debugfs/rcu/rsp/rcuboost'
to get the selected rsp info.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch add new 'rcubarrier' to each flavor's folder, now we could use:
'cat /debugfs/rcu/rsp/rcubarrier'
to get the selected rsp info.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The rcu_state structure's ->completed field is unsigned long, so this
commit adjusts show_one_rcugp()'s printf() format to suit. Also add
the required ACCESS_ONCE() directives while we are in this function.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch removes the interface "rcudata.csv" since it is apparently
not used.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch removed the old RCU debugfs interface and replaced it with
the new one.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch implements the new 'rcu_pending' interface under each rsp
directory, by using the 'CPU units sequence reading', thus avoiding loss
of tracing data.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch implements the new 'rcudata.csv' interface under each rsp
directory, by using the 'CPU units sequence reading', thus avoiding loss
of tracing data.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch implements the new 'rcudata' interface under each rsp
directory, by using the 'CPU units sequence reading', thus avoiding loss
of tracing data.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch add the fundamental facility used by the following patches, so we
can implement the 'CPU units sequence reading' later.
This helps us avoid losing data when there are too many CPUs and too
small of a buffer, since this new approach allows userspace to read out
the data one CPU at a time. Thus, if the buffer is not large enough,
userspace will get whatever CPUs fit, and can then issue another read
for the remainder of the data.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch will create subdirectory according to each flavor of rcu, the new
structure will be:
/debugfs/rcu/ -> rsp_0
-> rsp_1
-> ...
So we can go to '/debugfs/rcu/rsp_0' and get the cpu info of rsp_0 there.
The flavors of RCU are currently rcu_bh, rcu_preempt, and rcu_sched.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit adds the counters to rcu_state and updates them in
synchronize_rcu_expedited() to provide the data needed for debugfs
tracing.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tracing (debugfs) of expedited RCU primitives is required, which in turn
requires that the relevant data be located where the tracing code can find
it, not in its current static global variables in kernel/rcutree.c.
This commit therefore moves sync_sched_expedited_started and
sync_sched_expedited_done to the rcu_state structure, as fields
->expedited_start and ->expedited_done, respectively.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There is a counter scheme similar to ticket locking that
synchronize_sched_expedited() uses to service multiple concurrent
callers with the same expedited grace period. Upon entry, a
sync_sched_expedited_started variable is atomically incremented,
and upon completion of a expedited grace period a separate
sync_sched_expedited_done variable is atomically incremented.
However, if a synchronize_sched_expedited() is delayed while
in try_stop_cpus(), concurrent invocations will increment the
sync_sched_expedited_started counter, which will eventually overflow.
If the original synchronize_sched_expedited() resumes execution just
as the counter overflows, a concurrent invocation could incorrectly
conclude that an expedited grace period elapsed in zero time, which
would be bad. One could rely on counter size to prevent this from
happening in practice, but the goal is to formally validate this
code, so it needs to be fixed anyway.
This commit therefore checks the gap between the two counters before
incrementing sync_sched_expedited_started, and if the gap is too
large, does a normal grace period instead. Overflow is thus only
possible if there are more than about 3.5 billion threads on 32-bit
systems, which can be excluded until such time as task_struct fits
into a single byte and 4G/4G patches are accepted into mainline.
It is also easy to encode this limitation into mechanical theorem
provers.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The ->onofflock field in the rcu_state structure at one time synchronized
CPU-hotplug operations for RCU. However, its scope has decreased over time
so that it now only protects the lists of orphaned RCU callbacks. This
commit therefore renames it to ->orphan_lock to reflect its current use.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
'start' is set to buf + buflen and do the '--' immediately.
Just set it to 'buf + buflen - 1' directly.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Pull rmdir updates into for-3.8 so that further callback updates can
be put on top. This pull created a trivial conflict between the
following two commits.
8c7f6edbda ("cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them")
ed95779340 ("cgroup: kill cgroup_subsys->__DEPRECATED_clear_css_refs")
The former added a field to cgroup_subsys and the latter removed one
from it. They happen to be colocated causing the conflict. Keeping
what's added and removing what's removed resolves the conflict.
Signed-off-by: Tejun Heo <tj@kernel.org>
All ->pre_destory() implementations return 0 now, which is the only
allowed return value. Make it return void.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
CGRP_WAIT_ON_RMDIR is another kludge which was added to make cgroup
destruction rollback somewhat working. cgroup_rmdir() used to drain
CSS references and CGRP_WAIT_ON_RMDIR and the associated waitqueue and
helpers were used to allow the task performing rmdir to wait for the
next relevant event.
Unfortunately, the wait is visible to controllers too and the
mechanism got exposed to memcg by 887032670d ("cgroup avoid permanent
sleep at rmdir").
Now that the draining and retries are gone, CGRP_WAIT_ON_RMDIR is
unnecessary. Remove it and all the mechanisms supporting it. Note
that memcontrol.c changes are essentially revert of 887032670d
("cgroup avoid permanent sleep at rmdir").
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Because ->pre_destroy() could fail and can't be called under
cgroup_mutex, cgroup destruction did something very ugly.
1. Grab cgroup_mutex and verify it can be destroyed; fail otherwise.
2. Release cgroup_mutex and call ->pre_destroy().
3. Re-grab cgroup_mutex and verify it can still be destroyed; fail
otherwise.
4. Continue destroying.
In addition to being ugly, it has been always broken in various ways.
For example, memcg ->pre_destroy() expects the cgroup to be inactive
after it's done but tasks can be attached and detached between #2 and
#3 and the conditions that memcg verified in ->pre_destroy() might no
longer hold by the time control reaches #3.
Now that ->pre_destroy() is no longer allowed to fail. We can switch
to the following.
1. Grab cgroup_mutex and verify it can be destroyed; fail otherwise.
2. Deactivate CSS's and mark the cgroup removed thus preventing any
further operations which can invalidate the verification from #1.
3. Release cgroup_mutex and call ->pre_destroy().
4. Re-grab cgroup_mutex and continue destroying.
After this change, controllers can safely assume that ->pre_destroy()
will only be called only once for a given cgroup and, once
->pre_destroy() is called, the cgroup will stay dormant till it's
destroyed.
This removes the only reason ->pre_destroy() can fail - new task being
attached or child cgroup being created inbetween. Error out path is
removed and ->pre_destroy() invocation is open coded in
cgroup_rmdir().
v2: cgroup_call_pre_destroy() removal moved to this patch per Michal.
Commit message updated per Glauber.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>
This patch makes cgroup_create() fail if @parent is marked removed.
This is to prepare for further updates to cgroup_rmdir() path.
Note that this change isn't strictly necessary. cgroup can only be
created via mkdir and the removed marking and dentry removal happen
without releasing cgroup_mutex, so cgroup_create() can never race with
cgroup_rmdir(). Even after the scheduled updates to cgroup_rmdir(),
cgroup_mkdir() and cgroup_rmdir() are synchronized by i_mutex
rendering the added liveliness check unnecessary.
Do it anyway such that locking is contained inside cgroup proper and
we don't get nasty surprises if we ever grow another caller of
cgroup_create().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
CSS_REMOVED is one of the several contortions which were necessary to
support css reference draining on cgroup removal. All css->refcnts
which need draining should be deactivated and verified to equal zero
atomically w.r.t. css_tryget(). If any one isn't zero, all refcnts
needed to be re-activated and css_tryget() shouldn't fail in the
process.
This was achieved by letting css_tryget() busy-loop until either the
refcnt is reactivated (failed removal attempt) or CSS_REMOVED is set
(committing to removal).
Now that css refcnt draining is no longer used, there's no need for
atomic rollback mechanism. css_tryget() simply can look at the
reference count and fail if it's deactivated - it's never getting
re-activated.
This patch removes CSS_REMOVED and updates __css_tryget() to fail if
the refcnt is deactivated. As deactivation and removal are a single
step now, they no longer need to be protected against css_tryget()
happening from irq context. Remove local_irq_disable/enable() from
cgroup_rmdir().
Note that this removes css_is_removed() whose only user is VM_BUG_ON()
in memcontrol.c. We can replace it with a check on the refcnt but
given that the only use case is a debug assert, I think it's better to
simply unexport it.
v2: Comment updated and explanation on local_irq_disable/enable()
added per Michal Hocko.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
2ef37d3fe4 ("memcg: Simplify mem_cgroup_force_empty_list error
handling") removed the last user of __DEPRECATED_clear_css_refs. This
patch removes __DEPRECATED_clear_css_refs and mechanisms to support
it.
* Conditionals dependent on __DEPRECATED_clear_css_refs removed.
* cgroup_clear_css_refs() can no longer fail. All that needs to be
done are deactivating refcnts, setting CSS_REMOVED and putting the
base reference on each css. Remove cgroup_clear_css_refs() and the
failure path, and open-code the loops into cgroup_rmdir().
This patch keeps the two for_each_subsys() loops separate while open
coding them. They can be merged now but there are scheduled changes
which need them to be separate, so keep them separate to reduce the
amount of churn.
local_irq_save/restore() from cgroup_clear_css_refs() are replaced
with local_irq_disable/enable() for simplicity. This is safe as
cgroup_rmdir() is always called with IRQ enabled. Note that this IRQ
switching is necessary to ensure that css_tryget() isn't called from
IRQ context on the same CPU while lower context is between CSS
deactivation and setting CSS_REMOVED as css_tryget() would hang
forever in such cases waiting for CSS to be re-activated or
CSS_REMOVED set. This will go away soon.
v2: cgroup_call_pre_destroy() removal dropped per Michal. Commit
message updated to explain local_irq_disable/enable() conversion.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
No functional changes.
powerpc is the only user of arch_uprobe_enable/disable_step() helpers,
but they should die. They can not be used correctly, every arch needs
its own implementation (like x86 does). And they do not really help
even as initial-and-almost-working code, arch_uprobe_*_xol() hooks can
easily use user_enable/disable_single_step() directly.
Change arch_uprobe_*_step() to do nothing, and convert powerpc to use
ptrace helpers. This is equally wrong, powerpc needs the arch-specific
fixes.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Add trace_options to the kernel command line parameter to be able to
set options at early boot. For example, to enable stack dumps of
events, add the following:
trace_options=stacktrace
This along with the trace_event option, you can get not only
traces of the events but also the stack dumps with them.
Requested-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Have the ring buffer commit function use the irq_work infrastructure to
wake up any waiters waiting on the ring buffer for new data. The irq_work
was created for such a purpose, where doing the actual wake up at the
time of adding data is too dangerous, as an event or function trace may
be in the midst of the work queue locks and cause deadlocks. The irq_work
will either delay the action to the next timer interrupt, or trigger an IPI
to itself forcing an interrupt to do the work (in a safe location).
With irq_work, all ring buffer commits can safely do wakeups, removing
the need for the ring buffer commit "nowake" variants, which were used
by events and function tracing. All commits can now safely use the
normal commit, and the "nowake" variants can be removed.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The tracing_enabled file was used as a quick way to stop
tracers, and try to bring down overhead for things like
the latency tracers (irqsoff, wakeup, etc). But it didn't
work that well.
The tracing_on file was created as a really fast way to
stop recording into the ftrace ring buffer and can interact
with the kernel. That is a tracing_off() call in the kernel
can disable recording of events, and then from userspace one
could echo 1 into the tracing_on file to continue it. The
tracing_enabled function did too much to allow for this.
The tracing_on has taken over as a way to start and stop tracing
and the tracing_enabled file should not be used. But because of
its existance, it still confuses people. Over a year ago the
following commit was added:
commit 6752ab4a9c
Author: Steven Rostedt <srostedt@redhat.com>
Date: Tue Feb 8 13:54:06 2011 -0500
tracing: Deprecate tracing_enabled for tracing_on
This commit added a WARN_ON() if the tracing_enabled file's variable
was changed. After this was added, only LatencyTop complained, and
they soon fixed their tool as there was no reason that LatencyTop
should touch this file as it was using the perf ring buffers which
this file does not interact with. But since that time no one else
has complained about this WARN_ON(). Thus it is safe to assume that
this file is no longer needed. Time to get rid of it.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The tracing_enabled file has been deprecated as it never was able
to serve its purpose well. The tracing_on file has taken over.
Instead of having code to keep tracing_enabled, have the tracing_enabled
file just set tracing_on, and remove the tracing_enabled variable.
This allows us to remove the tracing_enabled file. The reason that
the remove is in a different change set and not removed here is
in case we find some lonely userspace tool that requires the file
to exist. Then the removal patch will get reverted, but this one
will not.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The function register_tracer() is only used by kernel core code,
that never needs to remove the tracer. As trace_events have become
the main way to add new tracing to the kernel, the need to
unregister a tracer has diminished. Remove the unused function
unregister_tracer(). If a need arises where we need it, then we
can always add it back.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The open function used by available_events is the same as set_event even
though it uses different seq functions. This causes a side effect of
writing into available_events clearing all events, even though
available_events is suppose to be read only.
There's no reason to keep a single function for just the open and have
both use different functions for everything else. It is a little
confusing and causes strange behavior. Just have each have their own
function.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
ring_buffer_oldest_event_ts() should return a value of u64 type, because
ring_buffer_per_cpu->buffer_page->buffer_data_page->time_stamp is u64 type.
Link: http://lkml.kernel.org/r/1349998076-15495-5-git-send-email-dhsharp@google.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: David Sharp <dhsharp@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Because the "tsc" clock isn't in nanoseconds, the ring buffer must be
reset when changing clocks so that incomparable timestamps don't end up
in the same trace.
Tested: Confirmed switching clocks resets the trace buffer.
Google-Bug-Id: 6980623
Link: http://lkml.kernel.org/r/1349998076-15495-3-git-send-email-dhsharp@google.com
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: David Sharp <dhsharp@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch removes the timecompare code from the kernel. The top five
reasons to do this are:
1. There are no more users of this code.
2. The original idea was a bit weak.
3. The original author has disappeared.
4. The code was not general purpose but tuned to a particular hardware,
5. There are better ways to accomplish clock synchronization.
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Tested-by: Bob Liu <lliubbo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In the comments of function tick_sched_timer(), the sentence
"timer->base->cpu_base->lock held" is not right.
In function __run_hrtimer(), before call timer->function(),
the cpu_base->lock has been unlocked.
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Cc: fei.li@intel.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1351098455.15558.1421.camel@cliu38-desktop-build
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
As irq_thread_check_affinity is called ONLY inside the while loop in
the irq thread, the core affinity is set only when an interrupt
occurs. This patch sets the core affinity right after the irq thread
is created and before it waits for interrupts. In real-tiime targets
that do not typically change the core affinity of irqs during
run-time, this patch will save additional latency of an irq thread in
setting the core affinity during the first interrupt occurrence for
that irq.
Signed-off-by: Sankara S Muthukrishnan <sankara.m@ni.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/CAFQPvXeVZ858WFYimEU5uvLNxLDd6bJMmqWihFmbCf3ntokz0A@mail.gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Attempts to retrigger nested threaded IRQs currently fail because they
have no primary handler. In order to support retrigger of nested
IRQs, the parent IRQ needs to be retriggered.
To fix, when an IRQ needs to be resent, if the interrupt has a parent
IRQ and runs in the context of the parent IRQ, then resend the parent.
Also, handle_nested_irq() needs to clear the replay flag like the
other handlers, otherwise check_irq_resend() will set it and it will
never be cleared. Without clearing, it results in the first resend
working fine, but check_irq_resend() returning early on subsequent
resends because the replay flag is still set.
Problem discovered on ARM/OMAP platforms where a nested IRQ that's
also a wakeup IRQ happens late in suspend and needed to be retriggered
during the resume process.
[khilman@ti.com: changelog edits, clear IRQS_REPLAY in handle_nested_irq()]
Reported-by: Kevin Hilman <khilman@ti.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1350425269-11489-1-git-send-email-khilman@deeprootsystems.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Siddhesh analyzed a failure in the take over of pi futexes in case the
owner died and provided a workaround.
See: http://sourceware.org/bugzilla/show_bug.cgi?id=14076
The detailed problem analysis shows:
Futex F is initialized with PTHREAD_PRIO_INHERIT and
PTHREAD_MUTEX_ROBUST_NP attributes.
T1 lock_futex_pi(F);
T2 lock_futex_pi(F);
--> T2 blocks on the futex and creates pi_state which is associated
to T1.
T1 exits
--> exit_robust_list() runs
--> Futex F userspace value TID field is set to 0 and
FUTEX_OWNER_DIED bit is set.
T3 lock_futex_pi(F);
--> Succeeds due to the check for F's userspace TID field == 0
--> Claims ownership of the futex and sets its own TID into the
userspace TID field of futex F
--> returns to user space
T1 --> exit_pi_state_list()
--> Transfers pi_state to waiter T2 and wakes T2 via
rt_mutex_unlock(&pi_state->mutex)
T2 --> acquires pi_state->mutex and gains real ownership of the
pi_state
--> Claims ownership of the futex and sets its own TID into the
userspace TID field of futex F
--> returns to user space
T3 --> observes inconsistent state
This problem is independent of UP/SMP, preemptible/non preemptible
kernels, or process shared vs. private. The only difference is that
certain configurations are more likely to expose it.
So as Siddhesh correctly analyzed the following check in
futex_lock_pi_atomic() is the culprit:
if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) {
We check the userspace value for a TID value of 0 and take over the
futex unconditionally if that's true.
AFAICT this check is there as it is correct for a different corner
case of futexes: the WAITERS bit became stale.
Now the proposed change
- if (unlikely(ownerdied || !(curval & FUTEX_TID_MASK))) {
+ if (unlikely(ownerdied ||
+ !(curval & (FUTEX_TID_MASK | FUTEX_WAITERS)))) {
solves the problem, but it's not obvious why and it wreckages the
"stale WAITERS bit" case.
What happens is, that due to the WAITERS bit being set (T2 is blocked
on that futex) it enforces T3 to go through lookup_pi_state(), which
in the above case returns an existing pi_state and therefor forces T3
to legitimately fight with T2 over the ownership of the pi_state (via
pi_state->mutex). Probelm solved!
Though that does not work for the "WAITERS bit is stale" problem
because if lookup_pi_state() does not find existing pi_state it
returns -ERSCH (due to TID == 0) which causes futex_lock_pi() to
return -ESRCH to user space because the OWNER_DIED bit is not set.
Now there is a different solution to that problem. Do not look at the
user space value at all and enforce a lookup of possibly available
pi_state. If pi_state can be found, then the new incoming locker T3
blocks on that pi_state and legitimately races with T2 to acquire the
rt_mutex and the pi_state and therefor the proper ownership of the
user space futex.
lookup_pi_state() has the correct order of checks. It first tries to
find a pi_state associated with the user space futex and only if that
fails it checks for futex TID value = 0. If no pi_state is available
nothing can create new state at that point because this happens with
the hash bucket lock held.
So the above scenario changes to:
T1 lock_futex_pi(F);
T2 lock_futex_pi(F);
--> T2 blocks on the futex and creates pi_state which is associated
to T1.
T1 exits
--> exit_robust_list() runs
--> Futex F userspace value TID field is set to 0 and
FUTEX_OWNER_DIED bit is set.
T3 lock_futex_pi(F);
--> Finds pi_state and blocks on pi_state->rt_mutex
T1 --> exit_pi_state_list()
--> Transfers pi_state to waiter T2 and wakes it via
rt_mutex_unlock(&pi_state->mutex)
T2 --> acquires pi_state->mutex and gains ownership of the pi_state
--> Claims ownership of the futex and sets its own TID into the
userspace TID field of futex F
--> returns to user space
This covers all gazillion points on which T3 might come in between
T1's exit_robust_list() clearing the TID field and T2 fixing it up. It
also solves the "WAITERS bit stale" problem by forcing the take over.
Another benefit of changing the code this way is that it makes it less
dependent on untrusted user space values and therefor minimizes the
possible wreckage which might be inflicted.
As usual after staring for too long at the futex code my brain hurts
so much that I really want to ditch that whole optimization of
avoiding the syscall for the non contended case for PI futexes and rip
out the maze of corner case handling code. Unfortunately we can't as
user space relies on that existing behaviour, but at least thinking
about it helps me to preserve my mental sanity. Maybe we should
nevertheless :)
Reported-and-tested-by: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1210232138540.2756@ionos
Acked-by: Darren Hart <dvhart@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The functions defined in include/trace/syscalls.h are not used directly
since struct ftrace_event_class was introduced. Remove them from the
header file and rearrange the ftrace_event_class declarations in
trace_syscalls.c.
Link: http://lkml.kernel.org/r/1339112785-21806-2-git-send-email-vnagarnaik@google.com
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Remove ftrace_format_syscall() declaration; it is neither defined nor
used. Also update a comment and formatting.
Link: http://lkml.kernel.org/r/1339112785-21806-1-git-send-email-vnagarnaik@google.com
Signed-off-by: David Sharp <dhsharp@google.com>
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Whenever an event is registered, the comm of tasks are saved at
every task switch instead of saving them at every event. But if
an event isn't executed much, the comm cache will be filled up
by tasks that did not record the event and you lose out on the comms
that did.
Here's an example, if you enable the following events:
echo 1 > /debug/tracing/events/kvm/kvm_cr/enable
echo 1 > /debug/tracing/events/net/net_dev_xmit/enable
Note, there's no kvm running on this machine so the first event will
never be triggered, but because it is enabled, the storing of comms
will continue. If we now disable the network event:
echo 0 > /debug/tracing/events/net/net_dev_xmit/enable
and look at the trace:
cat /debug/tracing/trace
sshd-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
sshd-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0
sshd-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0
sshd-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0
sshd-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0
We see that process 2672 which triggered the events has the comm "sshd".
But if we run hackbench for a bit and look again:
cat /debug/tracing/trace
<...>-2672 [001] ..s2 375.731616: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s1 375.731617: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s2 375.859356: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s1 375.859357: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s2 375.947351: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s1 375.947352: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s2 376.035383: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s1 376.035383: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=242 rc=0
<...>-2672 [001] ..s2 377.563806: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6de0 len=226 rc=0
<...>-2672 [001] ..s1 377.563807: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6de0 len=226 rc=0
<...>-2672 [001] ..s2 377.563834: net_dev_xmit: dev=eth0 skbaddr=ffff88005cbb6be0 len=114 rc=0
<...>-2672 [001] ..s1 377.563842: net_dev_xmit: dev=br0 skbaddr=ffff88005cbb6be0 len=114 rc=0
The stored "sshd" comm has been flushed out and we get a useless "<...>".
But by only storing comms after a trace event occurred, we can run
hackbench all day and still get the same output.
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The functon tracing_sched_wakeup_trace() does an open coded unlock
commit and save stack. This is what the trace_nowake_buffer_unlock_commit()
is for.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If comm recording is not enabled when trace_printk() is used then
you just get this type of output:
[ adding trace_printk("hello! %d", irq); in do_IRQ ]
<...>-2843 [001] d.h. 80.812300: do_IRQ: hello! 14
<...>-2734 [002] d.h2 80.824664: do_IRQ: hello! 14
<...>-2713 [003] d.h. 80.829971: do_IRQ: hello! 14
<...>-2814 [000] d.h. 80.833026: do_IRQ: hello! 14
By enabling the comm recorder when trace_printk is enabled:
hackbench-6715 [001] d.h. 193.233776: do_IRQ: hello! 21
sshd-2659 [001] d.h. 193.665862: do_IRQ: hello! 21
<idle>-0 [001] d.h1 193.665996: do_IRQ: hello! 21
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Since tracing is not used by 99% of Linux users, even though tracing
may be configured in, it does not make sense to allocate 1.4 Megs
per CPU for the ring buffers if they are not used. Thus, on boot up
the ring buffers are set to a minimal size until something needs the
and they are expanded.
This works well for events and tracers (function, etc), but for the
asynchronous use of trace_printk() which can write to the ring buffer
at any time, does not expand the buffers.
On boot up a check is made to see if any trace_printk() is used to
see if the trace_printk() temp buffer pages should be allocated. This
same code can be used to expand the buffers as well.
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The existing 'overrun' counter is incremented when the ring
buffer wraps around, with overflow on (the default). We wanted
a way to count requests lost from the buffer filling up with
overflow off, too. I decided to add a new counter instead
of retro-fitting the existing one because it seems like a
different statistic to count conceptually, and also because
of how the code was structured.
Link: http://lkml.kernel.org/r/1310765038-26399-1-git-send-email-slavapestov@google.com
Signed-off-by: Slava Pestov <slavapestov@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
print_max and use_max_tr in struct tracer are "int" variables and
used like flags. This is wasteful, so change the type to "bool".
Link: http://lkml.kernel.org/r/20121002082710.9807.86393.stgit@falsita
Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's times during debugging that it is helpful to see traces of early
boot functions. But the tracers are initialized at device_initcall()
which is quite late during the boot process. Setting the kernel command
line parameter ftrace=function will not show anything until the function
tracer is initialized. This prevents being able to trace functions before
device_initcall().
There's no reason that the tracers need to be initialized so late in the
boot process. Move them up to core_initcall() as they still need to come
after early_initcall() which initializes the tracing buffers.
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Masaki found and patched a kallsyms issue: the last symbol in a
module's symtab wasn't transferred. This is because we manually copy
the zero'th entry (which is always empty) then copy the rest in a loop
starting at 1, though from src[0]. His fix was minimal, I prefer to
rewrite the loops in more standard form.
There are two loops: one to get the size, and one to copy. Make these
identical: always count entry 0 and any defined symbol in an allocated
non-init section.
This bug exists since the following commit was introduced.
module: reduce symbol table for loaded modules (v2)
commit: 4a4962263f
LKML: http://lkml.org/lkml/2012/10/24/27
Reported-by: Masaki Kimura <masaki.kimura.kz@hitachi.com>
Cc: stable@kernel.org
Due to these two commits:
8323f26ce3 sched: Fix race in task_group()
800d4d30c8 sched, autogroup: Stop going ahead if autogroup is disabled
... autogroup scheduling's dynamic knobs are wrecked.
With both patches applied, all you have to do to crash a box is
disable autogroup during boot up, then reboot.. boom, NULL pointer
dereference due to 800d4d30 not allowing autogroup to move things,
and 8323f26ce making that the only way to switch runqueues.
Remove most of the (dysfunctional) knobs and turn the remaining
sched_autogroup_enabled knob readonly.
If the user fiddles with cgroups hereafter, once tasks
are moved, autogroup won't mess with them again unless
they call setsid().
No knobs, no glitz, nada, just a cute little thing folks can
turn on if they don't want to muck about with cgroups and/or
systemd.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Xiaotian Feng <xtfeng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xiaotian Feng <dannyfeng@tencent.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org> # v3.6
Link: http://lkml.kernel.org/r/1351451963.4999.8.camel@maggy.simpson.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
I've been trying to get hardware breakpoints with perf to work
on POWER7 but I'm getting the following:
% perf record -e mem:0x10000000 true
Error: sys_perf_event_open() syscall returned with 28 (No space left on device). /bin/dmesg may provide additional information.
Fatal: No CONFIG_PERF_EVENTS=y kernel support configured?
true: Terminated
(FWIW adding -a and it works fine)
Debugging it seems that __reserve_bp_slot() is returning ENOSPC
because it thinks there are no free breakpoint slots on this
CPU.
I have a 2 CPUs, so perf userspace is doing two perf_event_open
syscalls to add a counter to each CPU [1]. The first syscall
succeeds but the second is failing.
On this second syscall, fetch_bp_busy_slots() sets slots.pinned
to be 1, despite there being no breakpoint on this CPU. This is
because the call the task_bp_pinned, checks all CPUs, rather
than just the current CPU. POWER7 only has one hardware
breakpoint per CPU (ie. HBP_NUM=1), so we return ENOSPC.
The following patch fixes this by checking the associated CPU
for each breakpoint in task_bp_pinned. I'm not familiar with
this code, so it's provided as a reference to the above issue.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Jovi Zhang <bookjovi@gmail.com>
Cc: K Prasad <prasad@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1351268936-2956-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
vtime_account() doesn't have the same role in
CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_IRQ_TIME_ACCOUNTING.
In the first case it handles time accounting in any context. In
the second case it only handles irq time accounting.
So when vtime_account() is called from outside vtime_account_irq_*()
this call is pointless to CONFIG_IRQ_TIME_ACCOUNTING.
To fix the confusion, change vtime_account() to irqtime_account_irq()
in CONFIG_IRQ_TIME_ACCOUNTING. This way we ensure future account_vtime()
calls won't waste useless cycles in the irqtime APIs.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
With CONFIG_VIRT_CPU_ACCOUNTING, when vtime_account()
is called in irq entry/exit, we perform a check on the
context: if we are interrupting the idle task we
account the pending cputime to idle, otherwise account
to system time or its sub-areas: tsk->stime, hardirq time,
softirq time, ...
However this check for idle only concerns the hardirq entry
and softirq entry:
* Hardirq may directly interrupt the idle task, in which case
we need to flush the pending CPU time to idle.
* The idle task may be directly interrupted by a softirq if
it calls local_bh_enable(). There is probably no such call
in any idle task but we need to cover every case. Ksoftirqd
is not concerned because the idle time is flushed on context
switch and softirq in the end of hardirq have the idle time
already flushed from the hardirq entry.
In the other cases we always account to system/irq time:
* On hardirq exit we account the time to hardirq time.
* On softirq exit we account the time to softirq time.
To optimize this and avoid the indirect call to vtime_account()
and the checks it performs, specialize the vtime irq APIs and
only perform the check on irq entry. Irq exit can directly call
vtime_account_system().
CONFIG_IRQ_TIME_ACCOUNTING behaviour doesn't change and directly
maps to its own vtime_account() implementation. One may want
to take benefits from the new APIs to optimize irq time accounting
as well in the future.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
vtime_account_system() currently has only one caller with
vtime_account() which is irq safe.
Now we are going to call it from other places like kvm where
irqs are not always disabled by the time we account the cputime.
So let's make it irqsafe. The arch implementation part is now
prefixed with "__".
vtime_account_idle() arch implementation is prefixed accordingly
to stay consistent.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Use DEFINE_STATIC_SRCU() to simplify the rcutorture.c SRCU test code.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
try_to_freeze_tasks() and cgroup_freezer rely on scheduler locks
to ensure that a task doing STOPPED/TRACED -> RUNNING transition
can't escape freezing. This mostly works, but ptrace_stop() does
not necessarily call schedule(), it can change task->state back to
RUNNING and check freezing() without any lock/barrier in between.
We could add the necessary barrier, but this patch changes
ptrace_stop() and do_signal_stop() to use freezable_schedule().
This fixes the race, freezer_count() and freezer_should_skip()
carefully avoid the race.
And this simplifies the code, try_to_freeze_tasks/update_if_frozen
no longer need to use task_is_stopped_or_traced() checks with the
non trivial assumptions. We can rely on the mechanism which was
specially designed to mark the sleeping task as "frozen enough".
v2: As Tejun pointed out, we can also change get_signal_to_deliver()
and move try_to_freeze() up before 'relock' label.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Merge misc fixes from Andrew Morton:
"18 total. 15 fixes and some updates to a device_cgroup patchset which
bring it up to date with the version which I should have merged in the
first place."
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (18 patches)
fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check
gen_init_cpio: avoid stack overflow when expanding
drivers/rtc/rtc-imxdi.c: add missing spin lock initialization
mm, numa: avoid setting zone_reclaim_mode unless a node is sufficiently distant
pidns: limit the nesting depth of pid namespaces
drivers/dma/dw_dmac: make driver's endianness configurable
mm/mmu_notifier: allocate mmu_notifier in advance
tools/testing/selftests/epoll/test_epoll.c: fix build
UAPI: fix tools/vm/page-types.c
mm/page_alloc.c:alloc_contig_range(): return early for err path
rbtree: include linux/compiler.h for definition of __always_inline
genalloc: stop crashing the system when destroying a pool
backlight: ili9320: add missing SPI dependency
device_cgroup: add proper checking when changing default behavior
device_cgroup: stop using simple_strtoul()
device_cgroup: rename deny_all to behavior
cgroup: fix invalid rcu dereference
mm: fix XFS oops due to dirty pages without buffers on s390
If one includes documentation for an external tool, it should be
correct. This is not:
1. Overriding the input to rngd should typically be neither
necessary nor desired. This is especially so since newer
versions of rngd support a number of different *types* of sources.
2. The default kernel-exported device is called /dev/hwrng not
/dev/hwrandom nor /dev/hw_random (both of which were used in the
past; however, kernel and udev seem to have converged on
/dev/hwrng.)
Overall it is better if the documentation for rngd is kept with rngd
rather than in a kernel Makefile.
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
'struct pid' is a "variable sized struct" - a header with an array of
upids at the end.
The size of the array depends on a level (depth) of pid namespaces. Now a
level of pidns is not limited, so 'struct pid' can be more than one page.
Looks reasonable, that it should be less than a page. MAX_PIS_NS_LEVEL is
not calculated from PAGE_SIZE, because in this case it depends on
architectures, config options and it will be reduced, if someone adds a
new fields in struct pid or struct upid.
I suggest to set MAX_PIS_NS_LEVEL = 32, because it saves ability to expand
"struct pid" and it's more than enough for all known for me use-cases.
When someone finds a reasonable use case, we can add a config option or a
sysctl parameter.
In addition it will reduce the effect of another problem, when we have
many nested namespaces and the oldest one starts dying.
zap_pid_ns_processe will be called for each namespace and find_vpid will
be called for each process in a namespace. find_vpid will be called
minimum max_level^2 / 2 times. The reason of that is that when we found a
bit in pidmap, we can't determine this pidns is top for this process or it
isn't.
vpid is a heavy operation, so a fork bomb, which create many nested
namespace, can make a system inaccessible for a long time. For example my
system becomes inaccessible for a few minutes with 4000 processes.
[akpm@linux-foundation.org: return -EINVAL in response to excessive nesting, not -ENOMEM]
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There don't have any 'r' prefix in uprobe event naming, remove it.
Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Pull cgroup fixes from Tejun Heo:
"This pull request contains three fixes.
Two are reverts of task_lock() removal in cgroup fork path. The
optimizations incorrectly assumed that threadgroup_lock can protect
process forks (as opposed to thread creations) too. Further cleanup
of cgroup fork path is scheduled.
The third fixes cgroup emptiness notification loss."
* 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
Revert "cgroup: Remove task_lock() from cgroup_post_fork()"
Revert "cgroup: Drop task_lock(parent) on cgroup_fork()"
cgroup: notify_on_release may not be triggered in some cases
Pull workqueue fix from Tejun Heo:
"This pull request contains one patch from Dan Magenheimer to fix
cancel_delayed_work() regression introduced by its reimplementation
using try_to_grab_pending(). The reimplementation made it incorrectly
return %true when the work item is idle.
There aren't too many consumers of the return value but it broke at
least ramster."
* 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: cancel_delayed_work() should return %false if work item is idle
57b30ae77b ("workqueue: reimplement cancel_delayed_work() using
try_to_grab_pending()") made cancel_delayed_work() always return %true
unless someone else is also trying to cancel the work item, which is
broken - if the target work item is idle, the return value should be
%false.
try_to_grab_pending() indicates that the target work item was idle by
zero return value. Use it for return. Note that this brings
cancel_delayed_work() in line with __cancel_work_timer() in return
value handling.
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <444a6439-b1a4-4740-9e7e-bc37267cfe73@default>
Not a big deal, but since other __get_key_name() callers
use it lets be consistent.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20121020190519.GH25467@moon
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While per-entity load-tracking is generally useful, beyond computing shares
distribution, e.g. runnable based load-balance (in progress), governors,
power-management, etc.
These facilities are not yet consumers of this data. This may be trivially
reverted when the information is required; but avoid paying the overhead for
calculations we will not use until then.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141507.422162369@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
__update_entity_runnable_avg forms the core of maintaining an entity's runnable
load average. In this function we charge the accumulated run-time since last
update and handle appropriate decay. In some cases, e.g. a waking task, this
time interval may be much larger than our period unit.
Fortunately we can exploit some properties of our series to perform decay for a
blocked update in constant time and account the contribution for a running
update in essentially-constant* time.
[*]: For any running entity they should be performing updates at the tick which
gives us a soft limit of 1 jiffy between updates, and we can compute up to a
32 jiffy update in a single pass.
C program to generate the magic constants in the arrays:
#include <math.h>
#include <stdio.h>
#define N 32
#define WMULT_SHIFT 32
const long WMULT_CONST = ((1UL << N) - 1);
double y;
long runnable_avg_yN_inv[N];
void calc_mult_inv() {
int i;
double yn = 0;
printf("inverses\n");
for (i = 0; i < N; i++) {
yn = (double)WMULT_CONST * pow(y, i);
runnable_avg_yN_inv[i] = yn;
printf("%2d: 0x%8lx\n", i, runnable_avg_yN_inv[i]);
}
printf("\n");
}
long mult_inv(long c, int n) {
return (c * runnable_avg_yN_inv[n]) >> WMULT_SHIFT;
}
void calc_yn_sum(int n)
{
int i;
double sum = 0, sum_fl = 0, diff = 0;
/*
* We take the floored sum to ensure the sum of partial sums is never
* larger than the actual sum.
*/
printf("sum y^n\n");
printf(" %8s %8s %8s\n", "exact", "floor", "error");
for (i = 1; i <= n; i++) {
sum = (y * sum + y * 1024);
sum_fl = floor(y * sum_fl+ y * 1024);
printf("%2d: %8.0f %8.0f %8.0f\n", i, sum, sum_fl,
sum_fl - sum);
}
printf("\n");
}
void calc_conv(long n) {
long old_n;
int i = -1;
printf("convergence (LOAD_AVG_MAX, LOAD_AVG_MAX_N)\n");
do {
old_n = n;
n = mult_inv(n, 1) + 1024;
i++;
} while (n != old_n);
printf("%d> %ld\n", i - 1, n);
printf("\n");
}
void main() {
y = pow(0.5, 1/(double)N);
calc_mult_inv();
calc_conv(1024);
calc_yn_sum(N);
}
[ Compile with -lm ]
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141507.277808946@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that our measurement intervals are small (~1ms) we can amortize the posting
of update_shares() to be about each period overflow. This is a large cost
saving for frequently switching tasks.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141507.200772172@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that running entities maintain their own load-averages the work we must do
in update_shares() is largely restricted to the periodic decay of blocked
entities. This allows us to be a little less pessimistic regarding our
occupancy on rq->lock and the associated rq->clock updates required.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141507.133999170@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that the machinery in place is in place to compute contributed load in a
bottom up fashion; replace the shares distribution code within update_shares()
accordingly.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141507.061208672@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With bandwidth control tracked entities may cease execution according to user
specified bandwidth limits. Charging this time as either throttled or blocked
however, is incorrect and would falsely skew in either direction.
What we actually want is for any throttled periods to be "invisible" to
load-tracking as they are removed from the system for that interval and
contribute normally otherwise.
Do this by moderating the progression of time to omit any periods in which the
entity belonged to a throttled hierarchy.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.998912151@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Entities of equal weight should receive equitable distribution of cpu time.
This is challenging in the case of a task_group's shares as execution may be
occurring on multiple cpus simultaneously.
To handle this we divide up the shares into weights proportionate with the load
on each cfs_rq. This does not however, account for the fact that the sum of
the parts may be less than one cpu and so we need to normalize:
load(tg) = min(runnable_avg(tg), 1) * tg->shares
Where runnable_avg is the aggregate time in which the task_group had runnable
children.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.930124292@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Unlike task entities who have a fixed weight, group entities instead own a
fraction of their parenting task_group's shares as their contributed weight.
Compute this fraction so that we can correctly account hierarchies and shared
entity nodes.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.855074415@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Maintain a global running sum of the average load seen on each cfs_rq belonging
to each task group so that it may be used in calculating an appropriate
shares:weight distribution.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.792901086@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a running entity blocks we migrate its tracked load to
cfs_rq->blocked_runnable_avg. In the sleep case this occurs while holding
rq->lock and so is a natural transition. Wake-ups however, are potentially
asynchronous in the presence of migration and so special care must be taken.
We use an atomic counter to track such migrated load, taking care to match this
with the previously introduced decay counters so that we don't migrate too much
load.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.726077467@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since we are now doing bottom up load accumulation we need explicit
notification when a task has been re-parented so that the old hierarchy can be
updated.
Adds: migrate_task_rq(struct task_struct *p, int next_cpu)
(The alternative is to do this out of __set_task_cpu, but it was suggested that
this would be a cleaner encapsulation.)
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.660023400@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We are currently maintaining:
runnable_load(cfs_rq) = \Sum task_load(t)
For all running children t of cfs_rq. While this can be naturally updated for
tasks in a runnable state (as they are scheduled); this does not account for
the load contributed by blocked task entities.
This can be solved by introducing a separate accounting for blocked load:
blocked_load(cfs_rq) = \Sum runnable(b) * weight(b)
Obviously we do not want to iterate over all blocked entities to account for
their decay, we instead observe that:
runnable_load(t) = \Sum p_i*y^i
and that to account for an additional idle period we only need to compute:
y*runnable_load(t).
This means that we can compute all blocked entities at once by evaluating:
blocked_load(cfs_rq)` = y * blocked_load(cfs_rq)
Finally we maintain a decay counter so that when a sleeping entity re-awakens
we can determine how much of its load should be removed from the blocked sum.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.585389902@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For a given task t, we can compute its contribution to load as:
task_load(t) = runnable_avg(t) * weight(t)
On a parenting cfs_rq we can then aggregate:
runnable_load(cfs_rq) = \Sum task_load(t), for all runnable children t
Maintain this bottom up, with task entities adding their contributed load to
the parenting cfs_rq sum. When a task entity's load changes we add the same
delta to the maintained sum.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.514678907@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since runqueues do not have a corresponding sched_entity we instead embed a
sched_avg structure directly.
Signed-off-by: Ben Segall <bsegall@google.com>
Reviewed-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.442637130@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Instead of tracking averaging the load parented by a cfs_rq, we can track
entity load directly. With the load for a given cfs_rq then being the sum
of its children.
To do this we represent the historical contribution to runnable average
within each trailing 1024us of execution as the coefficients of a
geometric series.
We can express this for a given task t as:
runnable_sum(t) = \Sum u_i * y^i, runnable_avg_period(t) = \Sum 1024 * y^i
load(t) = weight_t * runnable_sum(t) / runnable_avg_period(t)
Where: u_i is the usage in the last i`th 1024us period (approximately 1ms)
~ms and y is chosen such that y^k = 1/2. We currently choose k to be 32 which
roughly translates to about a sched period.
Signed-off-by: Paul Turner <pjt@google.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120823141506.372695337@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In the comments of function tick_sched_timer(), the sentence
"timer->base->cpu_base->lock held" is not right.
In function __run_hrtimer(), before call timer->function(),
the cpu_base->lock has been unlocked.
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Cc: fei.li@intel.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1351098455.15558.1421.camel@cliu38-desktop-build
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Instead of BUG_ON(in_interrupt()), since that doesn't check for all
the newfangled stuff like preempt.
Note that this is valid since the console_sem is essentially used like
a real mutex with only two twists:
- we allow trylock from hardirq context
- across suspend/resume we lock the logical console_lock, but drop the
semaphore protecting the locking state.
Now that doesn't guarantee that no one is playing tricks in
single-thread atomic contexts at suspend/resume/boot time, but
- I couldn't find anything suspicious with some grepping,
- might_sleep shouldn't die,
- and I think the upside of catching more potential issues is worth
the risk of getting a might_sleep backtrace that would have been
save (and then dealing with that fallout).
Cc: Dave Airlie <airlied@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull perf fixes from Ingo Molnar:
"Most of these are uprobes race fixes from Oleg, and their preparatory
cleanups. (It's larger than what I'd normally send for an -rc kernel,
but they looked significant enough to not delay them.)
There's also an oprofile fix and an uncore PMU fix."
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
perf/x86: Disable uncore on virtualized CPUs
oprofile, x86: Fix wrapping bug in op_x86_get_ctrl()
ring-buffer: Check for uninitialized cpu buffer before resizing
uprobes: Fix the racy uprobe->flags manipulation
uprobes: Fix prepare_uprobe() race with itself
uprobes: Introduce prepare_uprobe()
uprobes: Fix handle_swbp() vs unregister() + register() race
uprobes: Do not delete uprobe if uprobe_unregister() fails
uprobes: Don't return success if alloc_uprobe() fails
uprobes/x86: Only rep+nop can be emulated correctly
uprobes: Simplify is_swbp_at_addr(), remove stale comments
uprobes: Kill set_orig_insn()->is_swbp_at_addr()
uprobes: Introduce copy_opcode(), kill read_opcode()
uprobes: Kill set_swbp()->is_swbp_at_addr()
uprobes: Restrict valid_vma(false) to skip VM_SHARED vmas
uprobes: Change valid_vma() to demand VM_MAYEXEC rather than VM_EXEC
uprobes: Change write_opcode() to use FOLL_FORCE
uprobes: Move clear_thread_flag(TIF_UPROBE) to uprobe_notify_resume()
uprobes: Kill UTASK_BP_HIT state
uprobes: Fix UPROBE_SKIP_SSTEP checks in handle_swbp()
...
In theory, if a grace period manages to get started despite there being
no callbacks on any of the CPUs, all CPUs could go into dyntick-idle
mode, so that the grace period would never end. This commit updates
the RCU CPU stall warning messages to detect this condition by summing
up the number of callbacks on all CPUs.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit causes the last grace period started and completed to be
printed on RCU CPU stall warning messages in order to aid diagnosis.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The RCU CPU stall warnings rely on trigger_all_cpu_backtrace() to
do NMI-based dump of the stack traces of all CPUs. Unfortunately, a
number of architectures do not implement trigger_all_cpu_backtrace(), in
which case RCU falls back to just dumping the stack of the running CPU.
This is unhelpful in the case where the running CPU has detected that
some other CPU has stalled.
This commit therefore makes the running CPU dump the stacks of the
tasks running on the stalled CPUs.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Because process_srcu() will be used in DEFINE_SRCU(), which is a macro
that could be expanded pretty much anywhere, it can no longer be static.
Note that process_srcu() is still internal to srcu.h.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Lai Jiangshan rewrote SRCU, so this commit ensures that he gets his
proper share of blame^Wcredit.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The fix introduced by a10d206e (rcu: Fix day-one dyntick-idle
stall-warning bug) has a C-language precedence error. It turns out
that this error is harmless in that the same result is computed for all
inputs, but the code is nevertheless a potential source of confusion.
This commit therefore introduces parentheses in order to force the
execution of the code to reflect the intent.
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
There have been some embedded applications that would benefit from
use of expedited grace-period primitives. In some ways, this is
similar to synchronize_net() doing either a normal or an expedited
grace period depending on lock state, but with control outside of
the kernel.
This commit therefore adds rcu_expedited boot and sysfs parameters
that cause the kernel to substitute expedited primitives for the
normal grace-period primitives.
[ paulmck: Add trace/event/rcu.h to kernel/srcu.c to avoid build error.
Get rid of infinite loop through contention path.]
Signed-off-by: Antti P Miettinen <amiettinen@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
It's only there to call rcu_user_hooks_switch(). Let's
just call rcu_user_hooks_switch() directly, we don't need this
function in the middle.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit causes rcutorture to print the errno if cpu_down() fails
when the rcutorture "verbose" module parameter is specified.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
In the old days, _rcu_barrier() acquired ->onofflock to exclude
rcu_send_cbs_to_orphanage(), which allowed the latter to avoid memory
barriers in callback handling. However, _rcu_barrier() recently started
doing get_online_cpus() to lock out CPU-hotplug operations entirely, which
means that the comment in rcu_send_cbs_to_orphanage() that talks about
->onofflock is now obsolete. This commit therefore fixes the comment.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Dave Airlie recently discovered a locking bug in the fbcon layer,
where a timer_del_sync (for the blinking cursor) deadlocks with the
timer itself, since both (want to) hold the console_lock:
https://lkml.org/lkml/2012/8/21/36
Unfortunately the console_lock isn't a plain mutex and hence has no
lockdep support. Which resulted in a few days wasted of tracking down
this bug (complicated by the fact that printk doesn't show anything
when the console is locked) instead of noticing the bug much earlier
with the lockdep splat.
Hence I've figured I need to fix that for the next deadlock involving
console_lock - and with kms/drm growing ever more complex locking
that'll eventually happen.
Now the console_lock has rather funky semantics, so after a quick irc
discussion with Thomas Gleixner and Dave Airlie I've quickly ditched
the original idead of switching to a real mutex (since it won't work)
and instead opted to annotate the console_lock with lockdep
information manually.
There are a few special cases:
- The console_lock state is protected by the console_sem, and usually
grabbed/dropped at _lock/_unlock time. But the suspend/resume code
drops the semaphore without dropping the console_lock (see
suspend_console/resume_console). But since the same thread that did
the suspend will do the resume, we don't need to fix up anything.
- In the printk code there's a special trylock, only used to kick off
the logbuffer printk'ing in console_unlock. But all that happens
while lockdep is disable (since printk does a few other evil
tricks). So no issue there, either.
- The console_lock can also be acquired form irq context (but only
with a trylock). lockdep already handles that.
This all leaves us with annotating the normal console_lock, _unlock
and _trylock functions.
And yes, it works - simply unloading a drm kms driver resulted in
lockdep complaining about the deadlock in fbcon_deinit:
======================================================
[ INFO: possible circular locking dependency detected ]
3.6.0-rc2+ #552 Not tainted
-------------------------------------------------------
kms-reload/3577 is trying to acquire lock:
((&info->queue)){+.+...}, at: [<ffffffff81058c70>] wait_on_work+0x0/0xa7
but task is already holding lock:
(console_lock){+.+.+.}, at: [<ffffffff81264686>] bind_con_driver+0x38/0x263
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (console_lock){+.+.+.}:
[<ffffffff81087440>] lock_acquire+0x95/0x105
[<ffffffff81040190>] console_lock+0x59/0x5b
[<ffffffff81209cb6>] fb_flashcursor+0x2e/0x12c
[<ffffffff81057c3e>] process_one_work+0x1d9/0x3b4
[<ffffffff810584a2>] worker_thread+0x1a7/0x24b
[<ffffffff8105ca29>] kthread+0x7f/0x87
[<ffffffff813b1204>] kernel_thread_helper+0x4/0x10
-> #0 ((&info->queue)){+.+...}:
[<ffffffff81086cb3>] __lock_acquire+0x999/0xcf6
[<ffffffff81087440>] lock_acquire+0x95/0x105
[<ffffffff81058cab>] wait_on_work+0x3b/0xa7
[<ffffffff81058dd6>] __cancel_work_timer+0xbf/0x102
[<ffffffff81058e33>] cancel_work_sync+0xb/0xd
[<ffffffff8120a3b3>] fbcon_deinit+0x11c/0x1dc
[<ffffffff81264793>] bind_con_driver+0x145/0x263
[<ffffffff81264a45>] unbind_con_driver+0x14f/0x195
[<ffffffff8126540c>] store_bind+0x1ad/0x1c1
[<ffffffff8127cbb7>] dev_attr_store+0x13/0x1f
[<ffffffff8116d884>] sysfs_write_file+0xe9/0x121
[<ffffffff811145b2>] vfs_write+0x9b/0xfd
[<ffffffff811147b7>] sys_write+0x3e/0x6b
[<ffffffff813b0039>] system_call_fastpath+0x16/0x1b
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(console_lock);
lock((&info->queue));
lock(console_lock);
lock((&info->queue));
*** DEADLOCK ***
v2: Mark the lockdep_map static, noticed by Jani Nikula.
Cc: Dave Airlie <airlied@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce struct pm_qos_flags_request and struct pm_qos_flags
representing PM QoS flags request type and PM QoS flags constraint
type, respectively. With these definitions the data structures
will be arranged so that the list member of a struct pm_qos_flags
object will contain the head of a list of struct pm_qos_flags_request
objects representing all of the "flags" requests present for the
given device. Then, the effective_flags member of a struct
pm_qos_flags object will contain the bitwise OR of the flags members
of all the struct pm_qos_flags_request objects in the list.
Additionally, introduce helper function pm_qos_update_flags()
allowing the caller to manage the list of struct pm_qos_flags_request
pointed to by the list member of struct pm_qos_flags.
The flags are of type s32 so that the request's "value" field
is always of the same type regardless of what kind of request it
is (latency requests already have value fields of type s32).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Jean Pihet <j-pihet@ti.com>
Acked-by: mark gross <markgross@thegnar.org>
Fix the warning:
kernel/module_signing.c:195:2: warning: format '%lu' expects type 'long unsigned int', but argument 3 has type 'size_t'
by using the proper 'z' modifier for printing a size_t.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
freezer_read/write() used cgroup_lock_live_group() to synchronize
against task migration into and out of the target cgroup.
cgroup_lock_live_group() grabs the internal cgroup lock and using it
from outside cgroup core leads to complex and fragile locking
dependency issues which are difficult to resolve.
Now that freezer_can_attach() is replaced with freezer_attach() and
update_if_frozen() updated, nothing requires excluding migration
against freezer state reads and changes.
This patch removes cgroup_lock_live_group() and the matching
cgroup_unlock() usages. The prone-to-bitrot, already outdated and
unnecessary global lock hierarchy documentation is replaced with
documentation in local scope.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Li Zefan <lizefan@huawei.com>
Locking will change such that migration can happen while
freezer_read/write() is in progress. This means that
update_if_frozen() can no longer assume that all tasks in the cgroup
coform to the current freezer state - newly migrated tasks which
haven't finished freezer_attach() yet might be in any state.
This patch updates update_if_frozen() such that it no longer verifies
task states against freezer state. It now simply decides whether
FREEZING stage is complete.
This removal of verification makes it meaningless to call from
freezer_change_state(). Drop it and move the fast exit test from
freezer_read() - the only left caller - to update_if_frozen().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Li Zefan <lizefan@huawei.com>
cgroup_freezer is one of the few users of cgroup_subsys->can_attach()
and uses it to prevent tasks from being migrated into or out of a
frozen cgroup. This makes cgroup_freezer cumbersome to use especially
when co-mounted with other controllers.
->can_attach() is problematic in general as it can make co-mounting
multiple cgroups difficult - migrating tasks may fail for reasons
completely irrelevant for other controllers. freezer_can_attach() in
particular is more problematic because it messes with cgroup internal
locking to ensure that the state verification performed at
freezer_can_attach() stays valid until migration is complete.
This patch replaces freezer_can_attach() with freezer_attach() so that
tasks are always allowed to migrate - they are nudged into the
conforming state from freezer_attach(). This means that there can be
tasks which are being migrated which don't conform to the current
cgroup_freezer state until freezer_attach() is complete. Under the
current locking scheme, the only such place is freezer_fork() which is
updated to handle such window.
While this patch doesn't remove the use of internal cgroup locking
from freezer_read/write() paths, it removes the requirement to keep
the freezer state constant while migrating and enables such change.
Note that this creates a userland visible behavior change - FROZEN
cgroup can no longer be used to lock migrations in and out of the
cgroup. This behavior change is intended. I don't think the feature
is necessary - userland should coordinate accesses to cgroup fs anyway
- and even if the feature is needed cgroup_freezer is the completely
wrong place to implement it.
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <1350426526-14254-1-git-send-email-tj@kernel.org>
Cc: Matt Helsley <matthltc@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Li Zefan <lizefan@huawei.com>
Because grace-period initialization is carried out by a separate
kthread, it might happen on a different CPU than the one that
had the callback needing a grace period -- which is where the
callback acceleration needs to happen.
Fortunately, rcu_start_gp() holds the root rcu_node structure's
->lock, which prevents a new grace period from starting. This
allows this function to safely determine that a grace period has
not yet started, which in turn allows it to fully accelerate any
callbacks that it has pending. This commit adds this acceleration.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The min/max call needed to have explicit types on some architectures
(e.g. mn10300). Use clamp_t instead to avoid the warning:
kernel/sys.c: In function 'override_release':
kernel/sys.c:1287:10: warning: comparison of distinct pointer types lacks a cast [enabled by default]
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Emit the magic string that indicates a module has a signature after the
signature data instead of before it. This allows module_sig_check() to
be made simpler and faster by the elimination of the search for the
magic string. Instead we just need to do a single memcmp().
This works because at the end of the signature data there is the
fixed-length signature information block. This block then falls
immediately prior to the magic number.
From the contents of the information block, it is trivial to calculate
the size of the signature data and thus the size of the actual module
data.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 7e3aa30ac8.
The commit incorrectly assumed that fork path always performed
threadgroup_change_begin/end() and depended on that for
synchronization against task exit and cgroup migration paths instead
of explicitly grabbing task_lock().
threadgroup_change is not locked when forking a new process (as
opposed to a new thread in the same process) and even if it were it
wouldn't be effective as different processes use different threadgroup
locks.
Revert the incorrect optimization.
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <20121008020000.GB2575@localhost>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: stable@vger.kernel.org
This reverts commit 7e381b0eb1.
The commit incorrectly assumed that fork path always performed
threadgroup_change_begin/end() and depended on that for
synchronization against task exit and cgroup migration paths instead
of explicitly grabbing task_lock().
threadgroup_change is not locked when forking a new process (as
opposed to a new thread in the same process) and even if it were it
wouldn't be effective as different processes use different threadgroup
locks.
Revert the incorrect optimization.
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <20121008020000.GB2575@localhost>
Acked-by: Li Zefan <lizefan@huawei.com>
Bitterly-Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: stable@vger.kernel.org
free_pid_ns() operates in a recursive fashion:
free_pid_ns(parent)
put_pid_ns(parent)
kref_put(&ns->kref, free_pid_ns);
free_pid_ns
thus if there was a huge nesting of namespaces the userspace may trigger
avalanche calling of free_pid_ns leading to kernel stack exhausting and a
panic eventually.
This patch turns the recursion into an iterative loop.
Based on a patch by Andrew Vagin.
[akpm@linux-foundation.org: export put_pid_ns() to modules]
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Calling uname() with the UNAME26 personality set allows a leak of kernel
stack contents. This fixes it by defensively calculating the length of
copy_to_user() call, making the len argument unsigned, and initializing
the stack buffer to zero (now technically unneeded, but hey, overkill).
CVE-2012-0957
Reported-by: PaX Team <pageexec@freemail.hu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The console_cpu_notify() function runs with interrupts disabled in the
CPU_DYING case. It therefore cannot block, for example, as will happen
when it calls console_lock(). Therefore, remove the CPU_DYING leg of
the switch statement to avoid this problem.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
notify_on_release must be triggered when the last process in a cgroup is
move to another. But if the first(and only) process in a cgroup is moved to
another, notify_on_release is not triggered.
# mkdir /cgroup/cpu/SRC
# mkdir /cgroup/cpu/DST
#
# echo 1 >/cgroup/cpu/SRC/notify_on_release
# echo 1 >/cgroup/cpu/DST/notify_on_release
#
# sleep 300 &
[1] 8629
#
# echo 8629 >/cgroup/cpu/SRC/tasks
# echo 8629 >/cgroup/cpu/DST/tasks
-> notify_on_release for /SRC must be triggered at this point,
but it isn't.
This is because put_css_set() is called before setting CGRP_RELEASABLE
in cgroup_task_migrate(), and is a regression introduce by the
commit:74a1166d(cgroups: make procs file writable), which was merged
into v3.0.
Cc: Ben Blum <bblum@andrew.cmu.edu>
Cc: <stable@vger.kernel.org> # v3.0.x and later
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup_freezer doesn't transition from FREEZING to FROZEN if the
cgroup contains PF_NOFREEZE tasks or tasks sleeping with
PF_FREEZER_SKIP set.
Only kernel tasks can be non-freezable (PF_NOFREEZE) and there's
nothing cgroup_freezer or userland can do about or to it. It's
pointless to stall the transition for PF_NOFREEZE tasks.
PF_FREEZER_SKIP indicates that the task can be skipped when
determining whether frozen state is reached. A task with
PF_FREEZER_SKIP is guaranteed to perform try_to_freeze() after it
wakes up and can be considered frozen much like stopped or traced
tasks. Note that a vfork parent uses PF_FREEZER_SKIP while waiting
for the child.
This updates update_if_frozen() such that it only considers freezable
tasks and treats %true freezer_should_skip() tasks as frozen.
This allows cgroups w/ kthreads and vfork parents successfully reach
FROZEN state.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
try_to_freeze_cgroup() has condition checks which are intended to fail
the write operation to freezer.state if there are tasks which can't be
frozen. The condition checks have been broken for quite some time
now. freeze_task() returns %false if the target task can't be frozen,
so num_cant_freeze_now is never incremented.
In addition, strangely, cgroup freezing proceeds even after the write
is failed, which is rather broken.
This patch rips out the non-working code intended to fail the write to
freezer.state when the cgroup contains non-freezable tasks and makes
it official that writes to freezer.state succeed whether there are
non-freezable tasks in the cgroup or not.
This leaves is_task_frozen_enough() with only one user -
upste_if_frozen(). Collapse it into the caller. Note that this
removes an extra call to freezing().
This doesn't cause any userland behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
cgroup core has a bug which violates a basic rule about event
notifications - when a new entity needs to be added, you add that to
the notification list first and then make the new entity conform to
the current state. If done in the reverse order, an event happening
inbetween will be lost.
cgroup_subsys->fork() is invoked way before the new task is added to
the css_set. Currently, cgroup_freezer is the only user of ->fork()
and uses it to make new tasks conform to the current state of the
freezer. If FROZEN state is requested while fork is in progress
between cgroup_fork_callbacks() and cgroup_post_fork(), the child
could escape freezing - the cgroup isn't frozen when ->fork() is
called and the freezer couldn't see the new task on the css_set.
This patch moves cgroup_subsys->fork() invocation to
cgroup_post_fork() after the new task is added to the css_set.
cgroup_fork_callbacks() is removed.
Because now a task may be migrated during cgroup_subsys->fork(),
freezer_fork() is updated so that it adheres to the usual RCU locking
and the rather pointless comment on why locking can be different there
is removed (if it doesn't make anything simpler, why even bother?).
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@vger.kernel.org
As per the recent discussion with Mike and Linus, make it easier to
test with/without this feature. No change in default behavior.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-izoxq4haeg4mTognnDbwcevt@git.kernel.org
This optimize a bit the high res tick sched handler.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Besides unifying code, this also adds the idle check before
processing idle accounting specifics on the low res handler.
This way we also generalize this part of the nohz code for
!CONFIG_HIGH_RES_TIMERS to prepare for the adaptive tickless
features.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Unify the duplicated timekeeping handling code of low and high res tick
sched handlers.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Pull module signing support from Rusty Russell:
"module signing is the highlight, but it's an all-over David Howells frenzy..."
Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG.
* 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits)
X.509: Fix indefinite length element skip error handling
X.509: Convert some printk calls to pr_devel
asymmetric keys: fix printk format warning
MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
MODSIGN: Make mrproper should remove generated files.
MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs
MODSIGN: Use the same digest for the autogen key sig as for the module sig
MODSIGN: Sign modules during the build process
MODSIGN: Provide a script for generating a key ID from an X.509 cert
MODSIGN: Implement module signature checking
MODSIGN: Provide module signing public keys to the kernel
MODSIGN: Automatically generate module signing keys if missing
MODSIGN: Provide Kconfig options
MODSIGN: Provide gitignore and make clean rules for extra files
MODSIGN: Add FIPS policy
module: signature checking hook
X.509: Add a crypto key parser for binary (DER) X.509 certificates
MPILIB: Provide a function to read raw data into an MPI
X.509: Add an ASN.1 decoder
X.509: Add simple ASN.1 grammar compiler
...
Cleanups
Clean up compile warnings in kgdboc.c and x86/kernel/kgdb.c
Add module event hooks for simplified debugging with gdb
Fixes
Fix kdb to stop paging with 'q' on bta and dmesg
Fix for data that scrolls off the vga console due to line wrapping
when using the kdb pager
New
The debug core registers for kernel module events which allows a
kernel aware gdb to automatically load symbols and break on entry
to a kernel module
Allow kgdboc=kdb to setup kdb on the vga console
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Merge tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb
Pull KGDB/KDB fixes and cleanups from Jason Wessel:
"Cleanups
- Clean up compile warnings in kgdboc.c and x86/kernel/kgdb.c
- Add module event hooks for simplified debugging with gdb
Fixes
- Fix kdb to stop paging with 'q' on bta and dmesg
- Fix for data that scrolls off the vga console due to line wrapping
when using the kdb pager
New
- The debug core registers for kernel module events which allows a
kernel aware gdb to automatically load symbols and break on entry
to a kernel module
- Allow kgdboc=kdb to setup kdb on the vga console"
* tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
tty/console: fix warnings in drivers/tty/serial/kgdboc.c
kdb,vt_console: Fix missed data due to pager overruns
kdb: Fix dmesg/bta scroll to quit with 'q'
kgdboc: Accept either kbd or kdb to activate the vga + keyboard kdb shell
kgdb,x86: fix warning about unused variable
mips,kgdb: fix recursive page fault with CONFIG_KPROBES
kgdb: Add module event hooks
Pull perf updates from Ingo Molnar:
"This tree includes some late late perf items that missed the first
round:
tools:
- Bash auto completion improvements, now we can auto complete the
tools long options, tracepoint event names, etc, from Namhyung Kim.
- Look up thread using tid instead of pid in 'perf sched'.
- Move global variables into a perf_kvm struct, from David Ahern.
- Hists refactorings, preparatory for improved 'diff' command, from
Jiri Olsa.
- Hists refactorings, preparatory for event group viewieng work, from
Namhyung Kim.
- Remove double negation on optional feature macro definitions, from
Namhyung Kim.
- Remove several cases of needless global variables, on most
builtins.
- misc fixes
kernel:
- sysfs support for IBS on AMD CPUs, from Robert Richter.
- Support for an upcoming Intel CPU, the Xeon-Phi / Knights Corner
HPC blade PMU, from Vince Weaver.
- misc fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
perf: Fix perf_cgroup_switch for sw-events
perf: Clarify perf_cpu_context::active_pmu usage by renaming it to ::unique_pmu
perf/AMD/IBS: Add sysfs support
perf hists: Add more helpers for hist entry stat
perf hists: Move he->stat.nr_events initialization to a template
perf hists: Introduce struct he_stat
perf diff: Removing the total_period argument from output code
perf tool: Add hpp interface to enable/disable hpp column
perf tools: Removing hists pair argument from output path
perf hists: Separate overhead and baseline columns
perf diff: Refactor diff displacement possition info
perf hists: Add struct hists pointer to struct hist_entry
perf tools: Complete tracepoint event names
perf/x86: Add support for Intel Xeon-Phi Knights Corner PMU
perf evlist: Remove some unused methods
perf evlist: Introduce add_newtp method
perf kvm: Move global variables into a perf_kvm struct
perf tools: Convert to BACKTRACE_SUPPORT
perf tools: Long option completion support for each subcommands
perf tools: Complete long option names of perf command
...
Pull third pile of kernel_execve() patches from Al Viro:
"The last bits of infrastructure for kernel_thread() et.al., with
alpha/arm/x86 use of those. Plus sanitizing the asm glue and
do_notify_resume() on alpha, fixing the "disabled irq while running
task_work stuff" breakage there.
At that point the rest of kernel_thread/kernel_execve/sys_execve work
can be done independently for different architectures. The only
pending bits that do depend on having all architectures converted are
restrictred to fs/* and kernel/* - that'll obviously have to wait for
the next cycle.
I thought we'd have to wait for all of them done before we start
eliminating the longjump-style insanity in kernel_execve(), but it
turned out there's a very simple way to do that without flagday-style
changes."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
alpha: switch to saner kernel_execve() semantics
arm: switch to saner kernel_execve() semantics
x86, um: convert to saner kernel_execve() semantics
infrastructure for saner ret_from_kernel_thread semantics
make sure that kernel_thread() callbacks call do_exit() themselves
make sure that we always have a return path from kernel_execve()
ppc: eeh_event should just use kthread_run()
don't bother with kernel_thread/kernel_execve for launching linuxrc
alpha: get rid of switch_stack argument of do_work_pending()
alpha: don't bother passing switch_stack separately from regs
alpha: take SIGPENDING/NOTIFY_RESUME loop into signal.c
alpha: simplify TIF_NEED_RESCHED handling
Pull third pile of VFS updates from Al Viro:
"Stuff from Jeff Layton, mostly. Sanitizing interplay between audit
and namei, removing a lot of insanity from audit_inode() mess and
getting things ready for his ESTALE patchset."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
procfs: don't need a PATH_MAX allocation to hold a string representation of an int
vfs: embed struct filename inside of names_cache allocation if possible
audit: make audit_inode take struct filename
vfs: make path_openat take a struct filename pointer
vfs: turn do_path_lookup into wrapper around struct filename variant
audit: allow audit code to satisfy getname requests from its names_list
vfs: define struct filename and have getname() return it
vfs: unexport getname and putname symbols
acct: constify the name arg to acct_on
vfs: allocate page instead of names_cache buffer in mount_block_root
audit: overhaul __audit_inode_child to accomodate retrying
audit: optimize audit_compare_dname_path
audit: make audit_compare_dname_path use parent_len helper
audit: remove dirlen argument to audit_compare_dname_path
audit: set the name_len in audit_inode for parent lookups
audit: add a new "type" field to audit_names struct
audit: reverse arguments to audit_inode_child
audit: no need to walk list in audit_inode if name is NULL
audit: pass in dentry to audit_copy_inode wherever possible
audit: remove unnecessary NULL ptr checks from do_path_lookup
Keep a pointer to the audit_names "slot" in struct filename.
Have all of the audit_inode callers pass a struct filename ponter to
audit_inode instead of a string pointer. If the aname field is already
populated, then we can skip walking the list altogether and just use it
directly.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
...and fix up the callers. For do_file_open_root, just declare a
struct filename on the stack and fill out the .name field. For
do_filp_open, make it also take a struct filename pointer, and fix up its
callers to call it appropriately.
For filp_open, add a variant that takes a struct filename pointer and turn
filp_open into a wrapper around it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently, if we call getname() on a userland string more than once,
we'll get multiple copies of the string and multiple audit_names
records.
Add a function that will allow the audit_names code to satisfy getname
requests using info from the audit_names list, avoiding a new allocation
and audit_names records.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.
For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.
This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.
Later, we'll add other information to the struct as it becomes
convenient.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* allow kernel_execve() leave the actual return to userland to
caller (selected by CONFIG_GENERIC_KERNEL_EXECVE). Callers
updated accordingly.
* architecture that does select GENERIC_KERNEL_EXECVE in its
Kconfig should have its ret_from_kernel_thread() do this:
call schedule_tail
call the callback left for it by copy_thread(); if it ever
returns, that's because it has just done successful kernel_execve()
jump to return from syscall
IOW, its only difference from ret_from_fork() is that it does call the
callback.
* such an architecture should also get rid of ret_from_kernel_execve()
and __ARCH_WANT_KERNEL_EXECVE
This is the last part of infrastructure patches in that area - from
that point on work on different architectures can live independently.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull timer core update from Thomas Gleixner:
- Bug fixes (one for a longstanding dead loop issue)
- Rework of time related vsyscalls
- Alarm timer updates
- Jiffies updates to remove compile time dependencies
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Cast raw_interval to u64 to avoid shift overflow
timers: Fix endless looping between cascade() and internal_add_timer()
time/jiffies: bring back unconditional LATCH definition
time: Convert x86_64 to using new update_vsyscall
time: Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems
time: Introduce new GENERIC_TIME_VSYSCALL
time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD
time: Move update_vsyscall definitions to timekeeper_internal.h
time: Move timekeeper structure to timekeeper_internal.h for vsyscall changes
jiffies: Remove compile time assumptions about CLOCK_TICK_RATE
jiffies: Kill unused TICK_USEC_TO_NSEC
alarmtimer: Rename alarmtimer_remove to alarmtimer_dequeue
alarmtimer: Remove unused helpers & defines
alarmtimer: Use hrtimer per-alarm instead of per-base
alarmtimer: Implement minimum alarm interval for allowing suspend
Pull scheduler fixes from Ingo Molnar:
"A CPU hotplug related crash fix and a nohz accounting fixlet."
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched: Update sched_domains_numa_masks[][] when new cpus are onlined
sched: Ensure 'sched_domains_numa_levels' is safe to use in other functions
nohz: Fix one jiffy count too far in idle cputime
Pull RCU fixes from Ingo Molnar:
"This tree includes a shutdown/cpu-hotplug deadlock fix and a
documentation fix."
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rcu: Advise most users not to enable RCU user mode
rcu: Grace-period initialization excludes only RCU notifier
It is possible to miss data when using the kdb pager. The kdb pager
does not pay attention to the maximum column constraint of the screen
or serial terminal. This result is not incrementing the shown lines
correctly and the pager will print more lines that fit on the screen.
Obviously that is less than useful when using a VGA console where you
cannot scroll back.
The pager will now look at the kdb_buffer string to see how many
characters are printed. It might not be perfect considering you can
output ASCII that might move the cursor position, but it is a
substantially better approximation for viewing dmesg and trace logs.
This also means that the vt screen needs to set the kdb COLUMNS
variable.
Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
If you press 'q' the pager should exit instead of printing everything
from dmesg which can really bog down a 9600 baud serial link.
The same is true for the bta command.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Allow gdb to auto load kernel modules when it is attached,
which makes it trivially easy to debug module init functions
or pre-set breakpoints in a kernel module that has not loaded yet.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
In order to accomodate retrying path-based syscalls, we need to add a
new "type" argument to audit_inode_child. This will tell us whether
we're looking for a child entry that represents a create or a delete.
If we find a parent, don't automatically assume that we need to create a
new entry. Instead, use the information we have to try to find an
existing entry first. Update it if one is found and create a new one if
not.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
In the cases where we already know the length of the parent, pass it as
a parm so we don't need to recompute it. In the cases where we don't
know the length, pass in AUDIT_NAME_FULL (-1) to indicate that it should
be determined.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Kees Cook