race condition that happens between enabling/disabling syscall tracepoints
and new process creations (the check to go into the ptrace path for a process
can be set when it shouldn't, or not set when it should). Not a major bug
but one that should be fixed and even applied to stable.
The other two patches are cleanup/fixes that are not that critical, but
for an -rc1 release would be nice to have. They both deal with syscall
tracepoints.
It also includes a patch to introduce a new macro for the TRACE_EVENT()
format called __field_struct(). Originally, __field() was used to record
any variable into a trace event, but with the addition of setting the
"is signed" attribute, the check causes anything but a primitive variable
to fail to compile. That is, structs and unions can't be used as they
once were. When the "is signed" check was introduce there were only
primitive variables being recorded. But that will change soon and it
was reported that __field() causes build failures.
To solve the __field() issue, __field_struct() is introduced to allow
trace_events to be able to record complex types too.
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Merge tag 'trace-fixes-v3.16-rc1-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing cleanups and fixes from Steven Rostedt:
"This includes three patches from Oleg Nesterov. The first is a fix to
a race condition that happens between enabling/disabling syscall
tracepoints and new process creations (the check to go into the ptrace
path for a process can be set when it shouldn't, or not set when it
should). Not a major bug but one that should be fixed and even
applied to stable.
The other two patches are cleanup/fixes that are not that critical,
but for an -rc1 release would be nice to have. They both deal with
syscall tracepoints.
It also includes a patch to introduce a new macro for the
TRACE_EVENT() format called __field_struct(). Originally, __field()
was used to record any variable into a trace event, but with the
addition of setting the "is signed" attribute, the check causes
anything but a primitive variable to fail to compile. That is,
structs and unions can't be used as they once were. When the "is
signed" check was introduce there were only primitive variables being
recorded. But that will change soon and it was reported that
__field() causes build failures.
To solve the __field() issue, __field_struct() is introduced to allow
trace_events to be able to record complex types too"
* tag 'trace-fixes-v3.16-rc1-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Add __field_struct macro for TRACE_EVENT()
tracing: syscall_regfunc() should not skip kernel threads
tracing: Change syscall_*regfunc() to check PF_KTHREAD and use for_each_process_thread()
tracing: Fix syscall_*regfunc() vs copy_process() race
A 'softlockup' is defined as a bug that causes the kernel to loop in
kernel mode for more than a predefined period to time, without giving
other tasks a chance to run.
Currently, upon detection of this condition by the per-cpu watchdog
task, debug information (including a stack trace) is sent to the system
log.
On some occasions, we have observed that the "victim" rather than the
actual "culprit" (i.e. the owner/holder of the contended resource) is
reported to the user. Often this information has proven to be
insufficient to assist debugging efforts.
To avoid loss of useful debug information, for architectures which
support NMI, this patch makes it possible to improve soft lockup
reporting. This is accomplished by issuing an NMI to each cpu to obtain
a stack trace.
If NMI is not supported we just revert back to the old method. A sysctl
and boot-time parameter is available to toggle this feature.
[dzickus@redhat.com: add CONFIG_SMP in certain areas]
[akpm@linux-foundation.org: additional CONFIG_SMP=n optimisations]
[mq@suse.cz: fix warning]
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jan Moskyto Matejka <mq@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oleg reports a division by zero error on zero-length write() to the
percpu_pagelist_fraction sysctl:
divide error: 0000 [#1] SMP DEBUG_PAGEALLOC
CPU: 1 PID: 9142 Comm: badarea_io Not tainted 3.15.0-rc2-vm-nfs+ #19
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: ffff8800d5aeb6e0 ti: ffff8800d87a2000 task.ti: ffff8800d87a2000
RIP: 0010: percpu_pagelist_fraction_sysctl_handler+0x84/0x120
RSP: 0018:ffff8800d87a3e78 EFLAGS: 00010246
RAX: 0000000000000f89 RBX: ffff88011f7fd000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000010
RBP: ffff8800d87a3e98 R08: ffffffff81d002c8 R09: ffff8800d87a3f50
R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000060
R13: ffffffff81c3c3e0 R14: ffffffff81cfddf8 R15: ffff8801193b0800
FS: 00007f614f1e9740(0000) GS:ffff88011f440000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f614f1fa000 CR3: 00000000d9291000 CR4: 00000000000006e0
Call Trace:
proc_sys_call_handler+0xb3/0xc0
proc_sys_write+0x14/0x20
vfs_write+0xba/0x1e0
SyS_write+0x46/0xb0
tracesys+0xe1/0xe6
However, if the percpu_pagelist_fraction sysctl is set by the user, it
is also impossible to restore it to the kernel default since the user
cannot write 0 to the sysctl.
This patch allows the user to write 0 to restore the default behavior.
It still requires a fraction equal to or larger than 8, however, as
stated by the documentation for sanity. If a value in the range [1, 7]
is written, the sysctl will return EINVAL.
This successfully solves the divide by zero issue at the same time.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Oleg Drokin <green@linuxhacker.ru>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Peter Wu noticed the following splat on his machine when updating
/proc/sys/kernel/watchdog_thresh:
BUG: sleeping function called from invalid context at mm/slub.c:965
in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: init
3 locks held by init/1:
#0: (sb_writers#3){.+.+.+}, at: [<ffffffff8117b663>] vfs_write+0x143/0x180
#1: (watchdog_proc_mutex){+.+.+.}, at: [<ffffffff810e02d3>] proc_dowatchdog+0x33/0x110
#2: (cpu_hotplug.lock){.+.+.+}, at: [<ffffffff810589c2>] get_online_cpus+0x32/0x80
Preemption disabled at:[<ffffffff810e0384>] proc_dowatchdog+0xe4/0x110
CPU: 0 PID: 1 Comm: init Not tainted 3.16.0-rc1-testing #34
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x4e/0x7a
__might_sleep+0x11d/0x190
kmem_cache_alloc_trace+0x4e/0x1e0
perf_event_alloc+0x55/0x440
perf_event_create_kernel_counter+0x26/0xe0
watchdog_nmi_enable+0x75/0x140
update_timers_all_cpus+0x53/0xa0
proc_dowatchdog+0xe4/0x110
proc_sys_call_handler+0xb3/0xc0
proc_sys_write+0x14/0x20
vfs_write+0xad/0x180
SyS_write+0x49/0xb0
system_call_fastpath+0x16/0x1b
NMI watchdog: disabled (cpu0): hardware events not enabled
What happened is after updating the watchdog_thresh, the lockup detector
is restarted to utilize the new value. Part of this process involved
disabling preemption. Once preemption was disabled, perf tried to
allocate a new event (as part of the restart). This caused the above
BUG_ON as you can't sleep with preemption disabled.
The preemption restriction seemed agressive as we are not doing anything
on that particular cpu, but with all the online cpus (which are
protected by the get_online_cpus lock). Remove the restriction and the
BUG_ON goes away.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Peter Wu <peter@lekensteyn.nl>
Tested-by: Peter Wu <peter@lekensteyn.nl>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org> [3.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To allow filtering of huge pages, makedumpfile must be able to identify
them in the dump. This can be done by checking the appropriate page
flag, so communicate its value to makedumpfile through the VMCOREINFO
interface.
There's only one small catch. Depending on how many page flags are
available on a given architecture, this bit can be called PG_head or
PG_compound.
I sent a similar patch back in 2012, but Eric Biederman did not like
using an #ifdef. So, this time I'm adding a common symbol
(PG_head_mask) instead.
See https://lkml.org/lkml/2012/11/28/91 for the previous version.
Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a race between the CPU offline code (within stop-machine) and
the smp-call-function code, which can lead to getting IPIs on the
outgoing CPU, *after* it has gone offline.
Specifically, this can happen when using
smp_call_function_single_async() to send the IPI, since this API allows
sending asynchronous IPIs from IRQ disabled contexts. The exact race
condition is described below.
During CPU offline, in stop-machine, we don't enforce any rule in the
_DISABLE_IRQ stage, regarding the order in which the outgoing CPU and
the other CPUs disable their local interrupts. Due to this, we can
encounter a situation in which an IPI is sent by one of the other CPUs
to the outgoing CPU (while it is *still* online), but the outgoing CPU
ends up noticing it only *after* it has gone offline.
CPU 1 CPU 2
(Online CPU) (CPU going offline)
Enter _PREPARE stage Enter _PREPARE stage
Enter _DISABLE_IRQ stage
=
Got a device interrupt, and | Didn't notice the IPI
the interrupt handler sent an | since interrupts were
IPI to CPU 2 using | disabled on this CPU.
smp_call_function_single_async() |
=
Enter _DISABLE_IRQ stage
Enter _RUN stage Enter _RUN stage
=
Busy loop with interrupts | Invoke take_cpu_down()
disabled. | and take CPU 2 offline
=
Enter _EXIT stage Enter _EXIT stage
Re-enable interrupts Re-enable interrupts
The pending IPI is noted
immediately, but alas,
the CPU is offline at
this point.
This of course, makes the smp-call-function IPI handler code running on
CPU 2 unhappy and it complains about "receiving an IPI on an offline
CPU".
One real example of the scenario on CPU 1 is the block layer's
complete-request call-path:
__blk_complete_request() [interrupt-handler]
raise_blk_irq()
smp_call_function_single_async()
However, if we look closely, the block layer does check that the target
CPU is online before firing the IPI. So in this case, it is actually
the unfortunate ordering/timing of events in the stop-machine phase that
leads to receiving IPIs after the target CPU has gone offline.
In reality, getting a late IPI on an offline CPU is not too bad by
itself (this can happen even due to hardware latencies in IPI
send-receive). It is a bug only if the target CPU really went offline
without executing all the callbacks queued on its list. (Note that a
CPU is free to execute its pending smp-call-function callbacks in a
batch, without waiting for the corresponding IPIs to arrive for each one
of those callbacks).
So, fixing this issue can be broken up into two parts:
1. Ensure that a CPU goes offline only after executing all the
callbacks queued on it.
2. Modify the warning condition in the smp-call-function IPI handler
code such that it warns only if an offline CPU got an IPI *and* that
CPU had gone offline with callbacks still pending in its queue.
Achieving part 1 is straight-forward - just flush (execute) all the
queued callbacks on the outgoing CPU in the CPU_DYING stage[1],
including those callbacks for which the source CPU's IPIs might not have
been received on the outgoing CPU yet. Once we do this, an IPI that
arrives late on the CPU going offline (either due to the race mentioned
above, or due to hardware latencies) will be completely harmless, since
the outgoing CPU would have executed all the queued callbacks before
going offline.
Overall, this fix (parts 1 and 2 put together) additionally guarantees
that we will see a warning only when the *IPI-sender code* is buggy -
that is, if it queues the callback _after_ the target CPU has gone
offline.
[1]. The CPU_DYING part needs a little more explanation: by the time we
execute the CPU_DYING notifier callbacks, the CPU would have already
been marked offline. But we want to flush out the pending callbacks at
this stage, ignoring the fact that the CPU is offline. So restructure
the IPI handler code so that we can by-pass the "is-cpu-offline?" check
in this particular case. (Of course, the right solution here is to fix
CPU hotplug to mark the CPU offline _after_ invoking the CPU_DYING
notifiers, but this requires a lot of audit to ensure that this change
doesn't break any existing code; hence lets go with the solution
proposed above until that is done).
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Suggested-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <mgalbraith@suse.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sachin Kamat <sachin.kamat@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull perf fixes from Ingo Molnar:
"This is larger than usual: the main reason are the ARM symbol lookup
speedups that came in late and were hard to resist.
There's also a kprobes fix and various tooling fixes, plus the minimal
re-enablement of the mmap2 support interface"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
x86/kprobes: Fix build errors and blacklist context_track_user
perf tests: Add test for closing dso objects on EMFILE error
perf tests: Add test for caching dso file descriptors
perf tests: Allow reuse of test_file function
perf tests: Spawn child for each test
perf tools: Add dso__data_* interface descriptons
perf tools: Allow to close dso fd in case of open failure
perf tools: Add file size check and factor dso__data_read_offset
perf tools: Cache dso data file descriptor
perf tools: Add global count of opened dso objects
perf tools: Add global list of opened dso objects
perf tools: Add data_fd into dso object
perf tools: Separate dso data related variables
perf tools: Cache register accesses for unwind processing
perf record: Fix to honor user freq/interval properly
perf timechart: Reflow documentation
perf probe: Improve error messages in --line option
perf probe: Improve an error message of perf probe --vars mode
perf probe: Show error code and description in verbose mode
perf probe: Improve error message for unknown member of data structure
...
Pull rtmutex fixes from Thomas Gleixner:
"Another three patches to make the rtmutex code more robust. That's
the last urgent fallout from the big futex/rtmutex investigation"
* 'locking-urgent-for-linus.patch' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rtmutex: Plug slow unlock race
rtmutex: Detect changes in the pi lock chain
rtmutex: Handle deadlock detection smarter
syscall_regfunc() ignores the kernel threads because "it has no effect",
see cc3b13c1 "Don't trace kernel thread syscalls" which added this check.
However, this means that a user-space task spawned by call_usermodehelper()
will run without TIF_SYSCALL_TRACEPOINT if sys_tracepoint_refcount != 0.
Remove this check. The unnecessary report from ret_from_fork path mentioned
by cc3b13c1 is no longer possible, see See commit fb45550d76 "make sure
that kernel_thread() callbacks call do_exit() themselves".
A kernel_thread() callback can only return and take the int_ret_from_sys_call
path after do_execve() succeeds, otherwise the kernel will crash. But in this
case it is no longer a kernel thread and thus is needs TIF_SYSCALL_TRACEPOINT.
Link: http://lkml.kernel.org/p/20140413185938.GD20668@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
1. Remove _irqsafe from syscall_regfunc/syscall_unregfunc,
read_lock(tasklist) doesn't need to disable irqs.
2. Change this code to avoid the deprecated do_each_thread()
and use for_each_process_thread() (stolen from the patch
from Frederic).
3. Change syscall_regfunc() to check PF_KTHREAD to skip
the kernel threads, ->mm != NULL is the common mistake.
Note: probably this check should be simply removed, needs
another patch.
[fweisbec@gmail.com: s/do_each_thread/for_each_process_thread/]
Link: http://lkml.kernel.org/p/20140413185918.GC20668@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
syscall_regfunc() and syscall_unregfunc() should set/clear
TIF_SYSCALL_TRACEPOINT system-wide, but do_each_thread() can race
with copy_process() and miss the new child which was not added to
the process/thread lists yet.
Change copy_process() to update the child's TIF_SYSCALL_TRACEPOINT
under tasklist.
Link: http://lkml.kernel.org/p/20140413185854.GB20668@redhat.com
Cc: stable@vger.kernel.org # 2.6.33
Fixes: a871bd33a6 "tracing: Add syscall tracepoints"
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
- Fix for an ia64 regression introduced during the 3.11 cycle by a
commit that modified the hardware initialization ordering and made
device discovery fail on some systems.
- Fix for a build problem on systems where the cpufreq-cpu0 driver
is built-in and the cpu-thermal driver is modular from Arnd Bergmann.
- Fix for a recently introduced computational mistake in the
intel_pstate driver that leads to excessive rounding errors from
Doug Smythies.
- Fix for a failure code path in cpufreq_update_policy() that fails
to unlock the locks acquired previously from Aaron Plattner.
- Fix for the cpuidle mvebu driver to use shorter state names which
will prevent the sysfs interface from returning mangled strings.
From Gregory Clement.
- ACPI LPSS driver fix to make sure that the I2C controllers
included in BayTrail SoCs are not held in the reset state while
they are being probed from Mika Westerberg.
- New kernel command line arguments making it possible to build
kernel images with hibernation and kASLR included at the same
time and to select which of them will be used via the command
line (they are still functionally mutually exclusive, though).
From Kees Cook.
- ACPI battery driver quirk for Acer Aspire V5-573G that fails
to send battery status change notifications timely from
Alexander Mezin.
- Two ACPI core cleanups from Christoph Jaeger and Fabian Frederick.
/
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Merge tag 'pm+acpi-3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes from Rafael Wysocki:
"These are fixes mostly (ia64 regression related to the ACPI
enumeration of devices, cpufreq regressions, fix for I2C controllers
included in Intel SoCs, mvebu cpuidle driver fix related to sysfs)
plus additional kernel command line arguments from Kees to make it
possible to build kernel images with hibernation and the kernel
address space randomization included simultaneously, a new ACPI
battery driver quirk for a system with a broken BIOS and a couple of
ACPI core cleanups.
Specifics:
- Fix for an ia64 regression introduced during the 3.11 cycle by a
commit that modified the hardware initialization ordering and made
device discovery fail on some systems.
- Fix for a build problem on systems where the cpufreq-cpu0 driver is
built-in and the cpu-thermal driver is modular from Arnd Bergmann.
- Fix for a recently introduced computational mistake in the
intel_pstate driver that leads to excessive rounding errors from
Doug Smythies.
- Fix for a failure code path in cpufreq_update_policy() that fails
to unlock the locks acquired previously from Aaron Plattner.
- Fix for the cpuidle mvebu driver to use shorter state names which
will prevent the sysfs interface from returning mangled strings.
From Gregory Clement.
- ACPI LPSS driver fix to make sure that the I2C controllers included
in BayTrail SoCs are not held in the reset state while they are
being probed from Mika Westerberg.
- New kernel command line arguments making it possible to build
kernel images with hibernation and kASLR included at the same time
and to select which of them will be used via the command line (they
are still functionally mutually exclusive, though). From Kees
Cook.
- ACPI battery driver quirk for Acer Aspire V5-573G that fails to
send battery status change notifications timely from Alexander
Mezin.
- Two ACPI core cleanups from Christoph Jaeger and Fabian Frederick"
* tag 'pm+acpi-3.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpuidle: mvebu: Fix the name of the states
cpufreq: unlock when failing cpufreq_update_policy()
intel_pstate: Correct rounding in busy calculation
ACPI: use kstrto*() instead of simple_strto*()
ACPI / processor replace __attribute__((packed)) by __packed
ACPI / battery: add quirk for Acer Aspire V5-573G
ACPI / battery: use callback for setting up quirks
ACPI / LPSS: Take I2C host controllers out of reset
x86, kaslr: boot-time selectable with hibernation
PM / hibernate: introduce "nohibernate" boot parameter
cpufreq: cpufreq-cpu0: fix CPU_THERMAL dependency
ACPI / ia64 / sba_iommu: Restore the working initialization ordering
Changes kASLR from being compile-time selectable (blocked by
CONFIG_HIBERNATION), to being boot-time selectable (with hibernation
available by default) via the "kaslr" kernel command line.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To support using kernel features that are not compatible with hibernation,
this creates the "nohibernate" kernel boot parameter to disable both
hibernation and resume. This allows hibernation support to be a boot-time
choice instead of only a compile-time choice.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When the rtmutex fast path is enabled the slow unlock function can
create the following situation:
spin_lock(foo->m->wait_lock);
foo->m->owner = NULL;
rt_mutex_lock(foo->m); <-- fast path
free = atomic_dec_and_test(foo->refcnt);
rt_mutex_unlock(foo->m); <-- fast path
if (free)
kfree(foo);
spin_unlock(foo->m->wait_lock); <--- Use after free.
Plug the race by changing the slow unlock to the following scheme:
while (!rt_mutex_has_waiters(m)) {
/* Clear the waiters bit in m->owner */
clear_rt_mutex_waiters(m);
owner = rt_mutex_owner(m);
spin_unlock(m->wait_lock);
if (cmpxchg(m->owner, owner, 0) == owner)
return;
spin_lock(m->wait_lock);
}
So in case of a new waiter incoming while the owner tries the slow
path unlock we have two situations:
unlock(wait_lock);
lock(wait_lock);
cmpxchg(p, owner, 0) == owner
mark_rt_mutex_waiters(lock);
acquire(lock);
Or:
unlock(wait_lock);
lock(wait_lock);
mark_rt_mutex_waiters(lock);
cmpxchg(p, owner, 0) != owner
enqueue_waiter();
unlock(wait_lock);
lock(wait_lock);
wakeup_next waiter();
unlock(wait_lock);
lock(wait_lock);
acquire(lock);
If the fast path is disabled, then the simple
m->owner = NULL;
unlock(m->wait_lock);
is sufficient as all access to m->owner is serialized via
m->wait_lock;
Also document and clarify the wakeup_next_waiter function as suggested
by Oleg Nesterov.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140611183852.937945560@linutronix.de
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This essentially reverts commit:
ecd50f714c ("kprobes, x86: Call exception_enter after kprobes handled")
since it causes build errors with CONFIG_CONTEXT_TRACKING and
that has been made from misunderstandings;
context_track_user_*() don't involve much in interrupt context,
it just returns if in_interrupt() is true.
Instead of changing the do_debug/int3(), this just adds
context_track_user_*() to kprobes blacklist, since those are
still can be called right before kprobes handles int3 and debug
exceptions, and probing those will cause an infinite loop.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20140614064711.7865.45957.stgit@kbuild-fedora.novalocal
Signed-off-by: Ingo Molnar <mingo@kernel.org>
if "possible cpus" is greater than actual CPUs (including offline CPUs).
Namhyung Kim did some reviews of the patches I sent this merge window and
found a memory leak and had a few clean ups.
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Merge tag 'trace-3.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing cleanups and bugfixes from Steven Rostedt:
"One bug fix that goes back to 3.10. Accessing a non existent buffer
if "possible cpus" is greater than actual CPUs (including offline
CPUs).
Namhyung Kim did some reviews of the patches I sent this merge window
and found a memory leak and had a few clean ups"
* tag 'trace-3.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix check of ftrace_trace_arrays list_empty() check
tracing: Fix leak of per cpu max data in instances
tracing: Cleanup saved_cmdlines_size changes
ring-buffer: Check if buffer exists before polling
Pull more scheduler updates from Ingo Molnar:
"Second round of scheduler changes:
- try-to-wakeup and IPI reduction speedups, from Andy Lutomirski
- continued power scheduling cleanups and refactorings, from Nicolas
Pitre
- misc fixes and enhancements"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Delete extraneous extern for to_ratio()
sched/idle: Optimize try-to-wake-up IPI
sched/idle: Simplify wake_up_idle_cpu()
sched/idle: Clear polling before descheduling the idle thread
sched, trace: Add a tracepoint for IPI-less remote wakeups
cpuidle: Set polling in poll_idle
sched: Remove redundant assignment to "rt_rq" in update_curr_rt(...)
sched: Rename capacity related flags
sched: Final power vs. capacity cleanups
sched: Remove remaining dubious usage of "power"
sched: Let 'struct sched_group_power' care about CPU capacity
sched/fair: Disambiguate existing/remaining "capacity" usage
sched/fair: Change "has_capacity" to "has_free_capacity"
sched/fair: Remove "power" from 'struct numa_stats'
sched: Fix signedness bug in yield_to()
sched/fair: Use time_after() in record_wakee()
sched/balancing: Reduce the rate of needless idle load balancing
sched/fair: Fix unlocked reads of some cfs_b->quota/period
Pull more perf updates from Ingo Molnar:
"A second round of perf updates:
- wide reaching kprobes sanitization and robustization, with the hope
of fixing all 'probe this function crashes the kernel' bugs, by
Masami Hiramatsu.
- uprobes updates from Oleg Nesterov: tmpfs support, corner case
fixes and robustization work.
- perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
et al:
* Add support to accumulate hist periods (Namhyung Kim)
* various fixes, refactorings and enhancements"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
perf: Differentiate exec() and non-exec() comm events
perf: Fix perf_event_comm() vs. exec() assumption
uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
perf/documentation: Add description for conditional branch filter
perf/x86: Add conditional branch filtering support
perf/tool: Add conditional branch filter 'cond' to perf record
perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
uprobes: Teach copy_insn() to support tmpfs
uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
perf/x86: Use common PMU interrupt disabled code
perf/ARM: Use common PMU interrupt disabled code
perf: Disable sampled events if no PMU interrupt
perf: Fix use after free in perf_remove_from_context()
perf tools: Fix 'make help' message error
perf record: Fix poll return value propagation
perf tools: Move elide bool into perf_hpp_fmt struct
perf tools: Remove elide setup for SORT_MODE__MEMORY mode
perf tools: Fix "==" into "=" in ui_browser__warning assignment
perf tools: Allow overriding sysfs and proc finding with env var
perf tools: Consider header files outside perf directory in tags target
...
Pull more locking changes from Ingo Molnar:
"This is the second round of locking tree updates for v3.16, offering
large system scalability improvements:
- optimistic spinning for rwsems, from Davidlohr Bueso.
- 'qrwlocks' core code and x86 enablement, from Waiman Long and PeterZ"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, locking/rwlocks: Enable qrwlocks on x86
locking/rwlocks: Introduce 'qrwlocks' - fair, queued rwlocks
locking/mutexes: Documentation update/rewrite
locking/rwsem: Fix checkpatch.pl warnings
locking/rwsem: Fix warnings for CONFIG_RWSEM_GENERIC_SPINLOCK
locking/rwsem: Support optimistic spinning
Pull networking updates from David Miller:
1) Seccomp BPF filters can now be JIT'd, from Alexei Starovoitov.
2) Multiqueue support in xen-netback and xen-netfront, from Andrew J
Benniston.
3) Allow tweaking of aggregation settings in cdc_ncm driver, from Bjørn
Mork.
4) BPF now has a "random" opcode, from Chema Gonzalez.
5) Add more BPF documentation and improve test framework, from Daniel
Borkmann.
6) Support TCP fastopen over ipv6, from Daniel Lee.
7) Add software TSO helper functions and use them to support software
TSO in mvneta and mv643xx_eth drivers. From Ezequiel Garcia.
8) Support software TSO in fec driver too, from Nimrod Andy.
9) Add Broadcom SYSTEMPORT driver, from Florian Fainelli.
10) Handle broadcasts more gracefully over macvlan when there are large
numbers of interfaces configured, from Herbert Xu.
11) Allow more control over fwmark used for non-socket based responses,
from Lorenzo Colitti.
12) Do TCP congestion window limiting based upon measurements, from Neal
Cardwell.
13) Support busy polling in SCTP, from Neal Horman.
14) Allow RSS key to be configured via ethtool, from Venkata Duvvuru.
15) Bridge promisc mode handling improvements from Vlad Yasevich.
16) Don't use inetpeer entries to implement ID generation any more, it
performs poorly, from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1522 commits)
rtnetlink: fix userspace API breakage for iproute2 < v3.9.0
tcp: fixing TLP's FIN recovery
net: fec: Add software TSO support
net: fec: Add Scatter/gather support
net: fec: Increase buffer descriptor entry number
net: fec: Factorize feature setting
net: fec: Enable IP header hardware checksum
net: fec: Factorize the .xmit transmit function
bridge: fix compile error when compiling without IPv6 support
bridge: fix smatch warning / potential null pointer dereference
via-rhine: fix full-duplex with autoneg disable
bnx2x: Enlarge the dorq threshold for VFs
bnx2x: Check for UNDI in uncommon branch
bnx2x: Fix 1G-baseT link
bnx2x: Fix link for KR with swapped polarity lane
sctp: Fix sk_ack_backlog wrap-around problem
net/core: Add VF link state control policy
net/fsl: xgmac_mdio is dependent on OF_MDIO
net/fsl: Make xgmac_mdio read error message useful
net_sched: drr: warn when qdisc is not work conserving
...
- I didn't remember correctly that the Hans de Goede's ACPI video
patches actually didn't flip the video.use_native_backlight
default, although we had discussed that and decided to do that.
Since I said we would do that in the previous PM+ACPI pull
request, make that change for real now.
- ACPI bus check notifications for PCI host bridges don't cause
the bus below the host bridge to be checked for changes as they
should because of a mistake in the ACPI-based PCI hotplug (ACPIPHP)
subsystem that forgets to add hotplug contexts to PCI host bridge
ACPI device objects. Create hotplug contexts for PCI host bridges
too as appropriate.
- Revert recent cpufreq commit related to the big.LITTLE cpufreq
driver that breaks arm64 builds.
- Fix for a regression in the ppc-corenet cpufreq driver introduced
during the 3.15 cycle and causing the driver to use the remainder
from do_div instead of the quotient. From Ed Swarthout.
- Resets triggered by panic activate a BUG_ON() in vmalloc.c on
systems where the ACPI reset register is located in memory address
space. Fix from Randy Wright.
- Fix for a problem with cpufreq governors that decisions made by
them may be suboptimal due to the fact that deferrable timers are
used by them for CPU load sampling. From Srivatsa S Bhat.
- Fix for a problem with the Tegra cpufreq driver where the CPU
frequency is temporarily switched to a "stable" level that
is different from both the initial and target frequencies
during transitions which causes udelay() to expire earlier than
it should sometimes. From Viresh Kumar.
- New trace points and rework of some existing trace points for
system suspend/resume profiling from Todd Brandt.
- Assorted cpufreq fixes and cleanups from Stratos Karafotis and
Viresh Kumar.
- Copyright notice update for suspend-and-cpuhotplug.txt from
Srivatsa S Bhat.
/
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Merge tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more ACPI and power management updates from Rafael Wysocki:
"These are fixups on top of the previous PM+ACPI pull request,
regression fixes (ACPI hotplug, cpufreq ppc-corenet), other bug fixes
(ACPI reset, cpufreq), new PM trace points for system suspend
profiling and a copyright notice update.
Specifics:
- I didn't remember correctly that the Hans de Goede's ACPI video
patches actually didn't flip the video.use_native_backlight
default, although we had discussed that and decided to do that.
Since I said we would do that in the previous PM+ACPI pull request,
make that change for real now.
- ACPI bus check notifications for PCI host bridges don't cause the
bus below the host bridge to be checked for changes as they should
because of a mistake in the ACPI-based PCI hotplug (ACPIPHP)
subsystem that forgets to add hotplug contexts to PCI host bridge
ACPI device objects. Create hotplug contexts for PCI host bridges
too as appropriate.
- Revert recent cpufreq commit related to the big.LITTLE cpufreq
driver that breaks arm64 builds.
- Fix for a regression in the ppc-corenet cpufreq driver introduced
during the 3.15 cycle and causing the driver to use the remainder
from do_div instead of the quotient. From Ed Swarthout.
- Resets triggered by panic activate a BUG_ON() in vmalloc.c on
systems where the ACPI reset register is located in memory address
space. Fix from Randy Wright.
- Fix for a problem with cpufreq governors that decisions made by
them may be suboptimal due to the fact that deferrable timers are
used by them for CPU load sampling. From Srivatsa S Bhat.
- Fix for a problem with the Tegra cpufreq driver where the CPU
frequency is temporarily switched to a "stable" level that is
different from both the initial and target frequencies during
transitions which causes udelay() to expire earlier than it should
sometimes. From Viresh Kumar.
- New trace points and rework of some existing trace points for
system suspend/resume profiling from Todd Brandt.
- Assorted cpufreq fixes and cleanups from Stratos Karafotis and
Viresh Kumar.
- Copyright notice update for suspend-and-cpuhotplug.txt from
Srivatsa S Bhat"
* tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / hotplug / PCI: Add hotplug contexts to PCI host bridges
PM / sleep: trace events for device PM callbacks
cpufreq: cpufreq-cpu0: remove dependency on THERMAL and REGULATOR
cpufreq: tegra: update comment for clarity
cpufreq: intel_pstate: Remove duplicate CPU ID check
cpufreq: Mark CPU0 driver with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag
PM / Documentation: Update copyright in suspend-and-cpuhotplug.txt
cpufreq: governor: remove copy_prev_load from 'struct cpu_dbs_common_info'
cpufreq: governor: Be friendly towards latency-sensitive bursty workloads
PM / sleep: trace events for suspend/resume
cpufreq: ppc-corenet-cpu-freq: do_div use quotient
Revert "cpufreq: Enable big.LITTLE cpufreq driver on arm64"
cpufreq: Tegra: implement intermediate frequency callbacks
cpufreq: add support for intermediate (stable) frequencies
ACPI / video: Change the default for video.use_native_backlight to 1
ACPI: Fix bug when ACPI reset register is implemented in system memory
Fix this dependency on the locking tree's smp_mb*() API changes:
kernel/sched/idle.c:247:3: error: implicit declaration of function ‘smp_mb__after_atomic’ [-Werror=implicit-function-declaration]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
re-add the perm check (we unified the module param and sysfs checks, but
the module ones were stronger so we weakened them temporarily).
Param parsing gets documented, and also "--" now forces args to be
handed to init (and ignored by the kernel).
Module NX/RO protections get tightened: we now set them before calling
parse_args().
Cheers,
Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux
Pull module updates from Rusty Russell:
"Most of this is cleaning up various driver sysfs permissions so we can
re-add the perm check (we unified the module param and sysfs checks,
but the module ones were stronger so we weakened them temporarily).
Param parsing gets documented, and also "--" now forces args to be
handed to init (and ignored by the kernel).
Module NX/RO protections get tightened: we now set them before calling
parse_args()"
* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
module: set nx before marking module MODULE_STATE_COMING.
samples/kobject/: avoid world-writable sysfs files.
drivers/hid/hid-picolcd_fb: avoid world-writable sysfs files.
drivers/staging/speakup/: avoid world-writable sysfs files.
drivers/regulator/virtual: avoid world-writable sysfs files.
drivers/scsi/pm8001/pm8001_ctl.c: avoid world-writable sysfs files.
drivers/hid/hid-lg4ff.c: avoid world-writable sysfs files.
drivers/video/fbdev/sm501fb.c: avoid world-writable sysfs files.
drivers/mtd/devices/docg3.c: avoid world-writable sysfs files.
speakup: fix incorrect perms on speakup_acntsa.c
cpumask.h: silence warning with -Wsign-compare
Documentation: Update kernel-parameters.tx
param: hand arguments after -- straight to init
modpost: Fix resource leak in read_dump()
Merge leftovers from Andrew Morton:
"A few leftovers: ocfs2, gcov, RTC"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
rtc: s5m: consolidate two device type switch statements
rtc: s5m: add support for S2MPS14 RTC
rtc: s5m: support different register layout
rtc: s5m: use shorter time of register update
rtc: s5m: remove undocumented time init on first boot
mfd/rtc: sec/s5m: rename SEC* symbols to S5M
gcov: add support for GCC 4.9
ocfs2/o2net: incorrect to terminate accepting connections loop upon rejecting an invalid one
This patch handles the gcov-related changes in GCC 4.9:
A new counter (time profile) is added. The total number is 9 now.
A new profile merge function __gcov_merge_time_profile is added.
See gcc/gcov-io.h and libgcc/libgcov-merge.c
For the first change, the layout of struct gcov_info is affected.
For the second one, a dummy function is added to kernel/gcov/base.c
similarly.
Signed-off-by: Yuan Pengfei <coolypf@qq.com>
Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kernel has no concept of capabilities with respect to inodes; inodes
exist independently of namespaces. For example, inode_capable(inode,
CAP_LINUX_IMMUTABLE) would be nonsense.
This patch changes inode_capable to check for uid and gid mappings and
renames it to capable_wrt_inode_uidgid, which should make it more
obvious what it does.
Fixes CVE-2014-4014.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: stable@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The check that tests if ftrace_trace_arrays is empty in
top_trace_array(), uses the .prev pointer:
if (list_empty(ftrace_trace_arrays.prev))
instead of testing the variable itself:
if (list_empty(&ftrace_trace_arrays))
Although it is technically correct, it is awkward and confusing.
Use the proper method.
Link: http://lkml.kernel.org/r/87oay1bas8.fsf@sejong.aot.lge.com
Reported-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The freeing of an instance, if max data is configured, there will be
per cpu data structures created. But these are not freed when the instance
is deleted, which causes a memory leak.
A new helper function is added that frees the individual buffers within a
trace array, instead of duplicating the code. This way changes made for one
are applied to the other (normal buffer vs max buffer).
Link: http://lkml.kernel.org/r/87k38pbake.fsf@sejong.aot.lge.com
Reported-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Fixes an easy DoS and possible information disclosure.
This does nothing about the broken state of x32 auditing.
eparis: If the admin has enabled auditd and has specifically loaded
audit rules. This bug has been around since before git. Wow...
Cc: stable@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The recent addition of saved_cmdlines_size file had some remaining
(minor - mostly coding style) issues. Fix them by passing pointer
name to sizeof() and using scnprintf().
Link: http://lkml.kernel.org/p/1402384295-23680-1-git-send-email-namhyung@kernel.org
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The per_cpu buffers are created one per possible CPU. But these do
not mean that those CPUs are online, nor do they even exist.
With the addition of the ring buffer polling, it assumes that the
caller polls on an existing buffer. But this is not the case if
the user reads trace_pipe from a CPU that does not exist, and this
causes the kernel to crash.
Simple fix is to check the cpu against buffer bitmask against to see
if the buffer was allocated or not and return -ENODEV if it is
not.
More updates were done to pass the -ENODEV back up to userspace.
Link: http://lkml.kernel.org/r/5393DB61.6060707@oracle.com
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
to help out the rest of the kernel to ease their use of trace events.
The big change for this release is the allowing of other tracers,
such as the latency tracers, to be used in the trace instances and allow
for function or function graph tracing to be in the top level
simultaneously.
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Merge tag 'trace-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"Lots of tweaks, small fixes, optimizations, and some helper functions
to help out the rest of the kernel to ease their use of trace events.
The big change for this release is the allowing of other tracers, such
as the latency tracers, to be used in the trace instances and allow
for function or function graph tracing to be in the top level
simultaneously"
* tag 'trace-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits)
tracing: Fix memory leak on instance deletion
tracing: Fix leak of ring buffer data when new instances creation fails
tracing/kprobes: Avoid self tests if tracing is disabled on boot up
tracing: Return error if ftrace_trace_arrays list is empty
tracing: Only calculate stats of tracepoint benchmarks for 2^32 times
tracing: Convert stddev into u64 in tracepoint benchmark
tracing: Introduce saved_cmdlines_size file
tracing: Add __get_dynamic_array_len() macro for trace events
tracing: Remove unused variable in trace_benchmark
tracing: Eliminate double free on failure of allocation on boot up
ftrace/x86: Call text_ip_addr() instead of the duplicated code
tracing: Print max callstack on stacktrace bug
tracing: Move locking of trace_cmdline_lock into start/stop seq calls
tracing: Try again for saved cmdline if failed due to locking
tracing: Have saved_cmdlines use the seq_read infrastructure
tracing: Add tracepoint benchmark tracepoint
tracing: Print nasty banner when trace_printk() is in use
tracing: Add funcgraph_tail option to print function name after closing braces
tracing: Eliminate duplicate TRACE_GRAPH_PRINT_xx defines
tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks
...
Pull cgroup updates from Tejun Heo:
"A lot of activities on cgroup side. Heavy restructuring including
locking simplification took place to improve the code base and enable
implementation of the unified hierarchy, which currently exists behind
a __DEVEL__ mount option. The core support is mostly complete but
individual controllers need further work. To explain the design and
rationales of the the unified hierarchy
Documentation/cgroups/unified-hierarchy.txt
is added.
Another notable change is css (cgroup_subsys_state - what each
controller uses to identify and interact with a cgroup) iteration
update. This is part of continuing updates on css object lifetime and
visibility. cgroup started with reference count draining on removal
way back and is now reaching a point where csses behave and are
iterated like normal refcnted objects albeit with some complexities to
allow distinguishing the state where they're being deleted. The css
iteration update isn't taken advantage of yet but is planned to be
used to simplify memcg significantly"
* 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (77 commits)
cgroup: disallow disabled controllers on the default hierarchy
cgroup: don't destroy the default root
cgroup: disallow debug controller on the default hierarchy
cgroup: clean up MAINTAINERS entries
cgroup: implement css_tryget()
device_cgroup: use css_has_online_children() instead of has_children()
cgroup: convert cgroup_has_live_children() into css_has_online_children()
cgroup: use CSS_ONLINE instead of CGRP_DEAD
cgroup: iterate cgroup_subsys_states directly
cgroup: introduce CSS_RELEASED and reduce css iteration fallback window
cgroup: move cgroup->serial_nr into cgroup_subsys_state
cgroup: link all cgroup_subsys_states in their sibling lists
cgroup: move cgroup->sibling and ->children into cgroup_subsys_state
cgroup: remove cgroup->parent
device_cgroup: remove direct access to cgroup->children
memcg: update memcg_has_children() to use css_next_child()
memcg: remove tasks/children test from mem_cgroup_force_empty()
cgroup: remove css_parent()
cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css
cgroup: use cgroup->self.refcnt for cgroup refcnting
...
Pull workqueue updates from Tejun Heo:
"Lai simplified worker destruction path and internal workqueue locking
and there are some other minor changes.
Except for the removal of some long-deprecated interfaces which
haven't had any in-kernel user for quite a while, there shouldn't be
any difference to workqueue users"
* 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
kernel/workqueue.c: pr_warning/pr_warn & printk/pr_info
workqueue: remove the confusing POOL_FREEZING
workqueue: rename first_worker() to first_idle_worker()
workqueue: remove unused work_clear_pending()
workqueue: remove unused WORK_CPU_END
workqueue: declare system_highpri_wq
workqueue: use generic attach/detach routine for rescuers
workqueue: separate pool-attaching code out from create_worker()
workqueue: rename manager_mutex to attach_mutex
workqueue: narrow the protection range of manager_mutex
workqueue: convert worker_idr to worker_ida
workqueue: separate iteration role from worker_idr
workqueue: destroy worker directly in the idle timeout handler
workqueue: async worker destruction
workqueue: destroy_worker() should destroy idle workers only
workqueue: use manager lock only to protect worker_idr
workqueue: Remove deprecated system_nrt[_freezable]_wq
workqueue: Remove deprecated flush[_delayed]_work_sync()
kernel/workqueue.c: pr_warning/pr_warn & printk/pr_info
workqueue: simplify wq_update_unbound_numa() by jumping to use_dfl_pwq if the target cpumask equals wq's
This reverts commit 3090ffb5a2.
Re-enable the mmap2 interface as we will have a user soon.
Since things have changed since perf disabled mmap2, small tweaks
to the revert had to be done:
o commit 9d4ecc88 forced (n!=8) to become (n<7)
o a new libunwind test needed updating to use mmap2 interface
Signed-off-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1401461382-209586-1-git-send-email-dzickus@redhat.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
The mmap2 interface was missing the protection and flags bits needed to
accurately determine if a mmap memory area was shared or private and
if it was readable or not.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
[tweaked patch to compile and wrote changelog]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1400526833-141779-2-git-send-email-dzickus@redhat.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
This function is supposed to return true if the new load imbalance is
worse than the old one. It didn't. I can only hope brown paper bags
are in style.
Now things converge much better on both the 4 node and 8 node systems.
I am not sure why this did not seem to impact specjbb performance on the
4 node system, which is the system I have full-time access to.
This bug was introduced recently, with commit e63da03639 ("sched/numa:
Allow task switch if load imbalance improves")
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.
* accumulated work in next: (6809 commits)
ufs: sb mutex merge + mutex_destroy
powerpc: update comments for generic idle conversion
cris: update comments for generic idle conversion
idle: remove cpu_idle() forward declarations
nbd: zero from and len fields in NBD_CMD_DISCONNECT.
mm: convert some level-less printks to pr_*
MAINTAINERS: adi-buildroot-devel is moderated
MAINTAINERS: add linux-api for review of API/ABI changes
mm/kmemleak-test.c: use pr_fmt for logging
fs/dlm/debug_fs.c: replace seq_printf by seq_puts
fs/dlm/lockspace.c: convert simple_str to kstr
fs/dlm/config.c: convert simple_str to kstr
mm: mark remap_file_pages() syscall as deprecated
mm: memcontrol: remove unnecessary memcg argument from soft limit functions
mm: memcontrol: clean up memcg zoneinfo lookup
mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
mm/mempool.c: update the kmemleak stack trace for mempool allocations
lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
mm: introduce kmemleak_update_trace()
mm/kmemleak.c: use %u to print ->checksum
...
When we walk the lock chain, we drop all locks after each step. So the
lock chain can change under us before we reacquire the locks. That's
harmless in principle as we just follow the wrong lock path. But it
can lead to a false positive in the dead lock detection logic:
T0 holds L0
T0 blocks on L1 held by T1
T1 blocks on L2 held by T2
T2 blocks on L3 held by T3
T4 blocks on L4 held by T4
Now we walk the chain
lock T1 -> lock L2 -> adjust L2 -> unlock T1 ->
lock T2 -> adjust T2 -> drop locks
T2 times out and blocks on L0
Now we continue:
lock T2 -> lock L0 -> deadlock detected, but it's not a deadlock at all.
Brad tried to work around that in the deadlock detection logic itself,
but the more I looked at it the less I liked it, because it's crystal
ball magic after the fact.
We actually can detect a chain change very simple:
lock T1 -> lock L2 -> adjust L2 -> unlock T1 -> lock T2 -> adjust T2 ->
next_lock = T2->pi_blocked_on->lock;
drop locks
T2 times out and blocks on L0
Now we continue:
lock T2 ->
if (next_lock != T2->pi_blocked_on->lock)
return;
So if we detect that T2 is now blocked on a different lock we stop the
chain walk. That's also correct in the following scenario:
lock T1 -> lock L2 -> adjust L2 -> unlock T1 -> lock T2 -> adjust T2 ->
next_lock = T2->pi_blocked_on->lock;
drop locks
T3 times out and drops L3
T2 acquires L3 and blocks on L4 now
Now we continue:
lock T2 ->
if (next_lock != T2->pi_blocked_on->lock)
return;
We don't have to follow up the chain at that point, because T2
propagated our priority up to T4 already.
[ Folded a cleanup patch from peterz ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Brad Mouring <bmouring@ni.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140605152801.930031935@linutronix.de
Cc: stable@vger.kernel.org
Even in the case when deadlock detection is not requested by the
caller, we can detect deadlocks. Right now the code stops the lock
chain walk and keeps the waiter enqueued, even on itself. Silly not to
yell when such a scenario is detected and to keep the waiter enqueued.
Return -EDEADLK unconditionally and handle it at the call sites.
The futex calls return -EDEADLK. The non futex ones dequeue the
waiter, throw a warning and put the task into a schedule loop.
Tagged for stable as it makes the code more robust.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Brad Mouring <bmouring@ni.com>
Link: http://lkml.kernel.org/r/20140605152801.836501969@linutronix.de
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
When an instance is created, it also gets a snapshot ring buffer
allocated (with minimum of pages). But when it is deleted the snapshot
buffer is not. There was a helper function added to match the allocation
of these ring buffers to a way to free them, but it wasn't used by
the deletion of an instance. Using that helper function solves this
memory leak.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This typedef is unnecessary and should just be removed.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
Use #include <linux/types.h> instead of <asm/types.h>
Signed-off-by: Paul McQuade <paulmcquad@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
schedstr, sleepstr and kvmstr are only used in strcmp & strlen
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds