Commit Graph

39287 Commits

Author SHA1 Message Date
Dmitry Osipenko 13dfd97a34 notifier: Add atomic_notifier_call_chain_is_empty()
Add atomic_notifier_call_chain_is_empty() that returns true if given
atomic call chain is empty.

The first user of this new notifier API function will be the kernel
power-off core code that will support power-off call chains. The core
code will need to check whether there is a power-off handler registered
at all in order to decide whether to halt machine or power it off.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-05-19 19:25:06 +02:00
Xiu Jianfeng 29ed17389c cgroup: Make cgroup_debug static
Make cgroup_debug static since it's only used in cgroup.c

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2022-05-18 06:59:20 -10:00
Jason A. Donenfeld d4150779e6 random32: use real rng for non-deterministic randomness
random32.c has two random number generators in it: one that is meant to
be used deterministically, with some predefined seed, and one that does
the same exact thing as random.c, except does it poorly. The first one
has some use cases. The second one no longer does and can be replaced
with calls to random.c's proper random number generator.

The relatively recent siphash-based bad random32.c code was added in
response to concerns that the prior random32.c was too deterministic.
Out of fears that random.c was (at the time) too slow, this code was
anonymously contributed. Then out of that emerged a kind of shadow
entropy gathering system, with its own tentacles throughout various net
code, added willy nilly.

Stop👏making👏bespoke👏random👏number👏generators👏.

Fortunately, recent advances in random.c mean that we can stop playing
with this sketchiness, and just use get_random_u32(), which is now fast
enough. In micro benchmarks using RDPMC, I'm seeing the same median
cycle count between the two functions, with the mean being _slightly_
higher due to batches refilling (which we can optimize further need be).
However, when doing *real* benchmarks of the net functions that actually
use these random numbers, the mean cycles actually *decreased* slightly
(with the median still staying the same), likely because the additional
prandom code means icache misses and complexity, whereas random.c is
generally already being used by something else nearby.

The biggest benefit of this is that there are many users of prandom who
probably should be using cryptographically secure random numbers. This
makes all of those accidental cases become secure by just flipping a
switch. Later on, we can do a tree-wide cleanup to remove the static
inline wrapper functions that this commit adds.

There are also some low-ish hanging fruits for making this even faster
in the future: a get_random_u16() function for use in the networking
stack will give a 2x performance boost there, using SIMD for ChaCha20
will let us compute 4 or 8 or 16 blocks of output in parallel, instead
of just one, giving us large buffers for cheap, and introducing a
get_random_*_bh() function that assumes irqs are already disabled will
shave off a few cycles for ordinary calls. These are things we can chip
away at down the road.

Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-18 15:53:52 +02:00
Julian Orth 69e9cd66ae audit,io_uring,io-wq: call __audit_uring_exit for dummy contexts
Not calling the function for dummy contexts will cause the context to
not be reset. During the next syscall, this will cause an error in
__audit_syscall_entry:

	WARN_ON(context->context != AUDIT_CTX_UNUSED);
	WARN_ON(context->name_count);
	if (context->context != AUDIT_CTX_UNUSED || context->name_count) {
		audit_panic("unrecoverable error in audit_syscall_entry()");
		return;
	}

These problematic dummy contexts are created via the following call
chain:

       exit_to_user_mode_prepare
    -> arch_do_signal_or_restart
    -> get_signal
    -> task_work_run
    -> tctx_task_work
    -> io_req_task_submit
    -> io_issue_sqe
    -> audit_uring_entry

Cc: stable@vger.kernel.org
Fixes: 5bd2182d58 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Julian Orth <ju.orth@gmail.com>
[PM: subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-17 15:03:36 -04:00
Tianyu Lan 82806744fd swiotlb: max mapping size takes min align mask into account
swiotlb_find_slots() skips slots according to io tlb aligned mask
calculated from min aligned mask and original physical address
offset. This affects max mapping size. The mapping size can't
achieve the IO_TLB_SEGSIZE * IO_TLB_SIZE when original offset is
non-zero. This will cause system boot up failure in Hyper-V
Isolation VM where swiotlb force is enabled. Scsi layer use return
value of dma_max_mapping_size() to set max segment size and it
finally calls swiotlb_max_mapping_size(). Hyper-V storage driver
sets min align mask to 4k - 1. Scsi layer may pass 256k length of
request buffer with 0~4k offset and Hyper-V storage driver can't
get swiotlb bounce buffer via DMA API. Swiotlb_find_slots() can't
find 256k length bounce buffer with offset. Make swiotlb_max_mapping
_size() take min align mask into account.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-05-17 11:21:52 +02:00
Marco Elver 2434031c7c kcsan: test: use new suite_{init,exit} support
Use the newly added suite_{init,exit} support for suite-wide init and
cleanup. This avoids the unsupported method by which the test used to do
suite-wide init and cleanup (avoiding issues such as missing TAP
headers, and possible future conflicts).

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
2022-05-16 13:23:49 -06:00
Linus Torvalds 990e798d18 The recent expansion of the sched switch tracepoint inserted a new argument
in the middle of the arguments. This reordering broke BPF programs which
 relied on the old argument list. While tracepoints are not considered
 stable ABI, it's not trivial to make BPF cope with such a change, but it's
 being worked on. For now restore the original argument order and move the
 new argument to the end of the argument list.
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Merge tag 'sched-urgent-2022-05-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Thomas Gleixner:
 "The recent expansion of the sched switch tracepoint inserted a new
  argument in the middle of the arguments. This reordering broke BPF
  programs which relied on the old argument list.

  While tracepoints are not considered stable ABI, it's not trivial to
  make BPF cope with such a change, but it's being worked on. For now
  restore the original argument order and move the new argument to the
  end of the argument list"

* tag 'sched-urgent-2022-05-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/tracing: Append prev_state to tp args instead
2022-05-15 06:40:11 -07:00
Linus Torvalds fb756280f9 A single fix for a recent (introduced in 5.16) regression in the core
interrupt code. The consolidation of the interrupt handler invocation code
 added an unconditional warning when generic_handle_domain_irq() is invoked
 from outside hard interrupt context. That's overbroad as the requirement
 for invoking these handlers in hard interrupt context is only required for
 certain interrupt types. The subsequently called code already contains a
 warning which triggers conditionally for interrupt chips which indicate
 this requirement in their properties. Remove the overbroad one.
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Merge tag 'irq-urgent-2022-05-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fix from Thomas Gleixner:
 "A single fix for a recent (introduced in 5.16) regression in the core
  interrupt code.

  The consolidation of the interrupt handler invocation code added an
  unconditional warning when generic_handle_domain_irq() is invoked from
  outside hard interrupt context. That's overbroad as the requirement
  for invoking these handlers in hard interrupt context is only required
  for certain interrupt types. The subsequently called code already
  contains a warning which triggers conditionally for interrupt chips
  which indicate this requirement in their properties.

  Remove the overbroad one"

* tag 'irq-urgent-2022-05-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Remove WARN_ON_ONCE() in generic_handle_domain_irq()
2022-05-15 06:37:05 -07:00
Sebastian Andrzej Siewior 21673fcb25 genirq/irq_sim: Make the irq_work always run in hard irq context
The IRQ simulator uses irq_work to trigger an interrupt. Without the
IRQ_WORK_HARD_IRQ flag the irq_work will be performed in thread context
on PREEMPT_RT. This causes locking errors later in handle_simple_irq()
which expects to be invoked with disabled interrupts.

Triggering individual interrupts in hardirq context should not lead to
unexpected high latencies since this is also what the hardware
controller does. Also it is used as a simulator so...

Use IRQ_WORK_INIT_HARD() to carry out the irq_work in hardirq context on
PREEMPT_RT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/YnuZBoEVMGwKkLm+@linutronix.de
2022-05-14 17:48:27 +02:00
Stephen Boyd 317f29c14d timers: Provide a better debugobjects hint for delayed works
With debugobjects enabled the timer hint for freeing of active timers
embedded inside delayed works is always the same, i.e. the hint is
delayed_work_timer_fn, even though the function the delayed work is going
to run can be wildly different depending on what work was queued.  Enabling
workqueue debugobjects doesn't help either because the delayed work isn't
considered active until it is actually queued to run on a workqueue. If the
work is freed while the timer is pending the work isn't considered active
so there is no information from workqueue debugobjects.

Special case delayed works in the timer debugobjects hint logic so that the
delayed work function is returned instead of the delayed_work_timer_fn.
This will help to understand which delayed work was pending that got
freed.

Apply the same treatment for kthread_delayed_work because it follows the
same pattern.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220511201951.42408-1-swboyd@chromium.org
2022-05-14 17:40:36 +02:00
Joanne Koong 16d1e00c7e bpf: Add MEM_UNINIT as a bpf_type_flag
Instead of having uninitialized versions of arguments as separate
bpf_arg_types (eg ARG_PTR_TO_UNINIT_MEM as the uninitialized version
of ARG_PTR_TO_MEM), we can instead use MEM_UNINIT as a bpf_type_flag
modifier to denote that the argument is uninitialized.

Doing so cleans up some of the logic in the verifier. We no longer
need to do two checks against an argument type (eg "if
(base_type(arg_type) == ARG_PTR_TO_MEM || base_type(arg_type) ==
ARG_PTR_TO_UNINIT_MEM)"), since uninitialized and initialized
versions of the same argument type will now share the same base type.

In the near future, MEM_UNINIT will be used by dynptr helper functions
as well.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20220509224257.3222614-2-joannelkoong@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-13 15:56:26 -07:00
Jason A. Donenfeld 1366992e16 timekeeping: Add raw clock fallback for random_get_entropy()
The addition of random_get_entropy_fallback() provides access to
whichever time source has the highest frequency, which is useful for
gathering entropy on platforms without available cycle counters. It's
not necessarily as good as being able to quickly access a cycle counter
that the CPU has, but it's still something, even when it falls back to
being jiffies-based.

In the event that a given arch does not define get_cycles(), falling
back to the get_cycles() default implementation that returns 0 is really
not the best we can do. Instead, at least calling
random_get_entropy_fallback() would be preferable, because that always
needs to return _something_, even falling back to jiffies eventually.
It's not as though random_get_entropy_fallback() is super high precision
or guaranteed to be entropic, but basically anything that's not zero all
the time is better than returning zero all the time.

Finally, since random_get_entropy_fallback() is used during extremely
early boot when randomizing freelists in mm_init(), it can be called
before timekeeping has been initialized. In that case there really is
nothing we can do; jiffies hasn't even started ticking yet. So just give
up and return 0.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Theodore Ts'o <tytso@mit.edu>
2022-05-13 23:59:23 +02:00
Peter Collingbourne 534aa1dc97 printk: stop including cache.h from printk.h
An inclusion of cache.h in printk.h was added in 2014 in commit
c28aa1f0a8 ("printk/cache: mark printk_once test variable
__read_mostly") in order to bring in the definition of __read_mostly.  The
usage of __read_mostly was later removed in commit 3ec25826ae ("printk:
Tie printk_once / printk_deferred_once into .data.once for reset") which
made the inclusion of cache.h unnecessary, so remove it.

We have a small amount of code that depended on the inclusion of cache.h
from printk.h; fix that code to include the appropriate header.

This fixes a circular inclusion on arm64 (linux/printk.h -> linux/cache.h
-> asm/cache.h -> linux/kasan-enabled.h -> linux/static_key.h ->
linux/jump_label.h -> linux/bug.h -> asm/bug.h -> linux/printk.h) that
would otherwise be introduced by the next patch.

Build tested using {allyesconfig,defconfig} x {arm64,x86_64}.

Link: https://linux-review.googlesource.com/id/I8fd51f72c9ef1f2d6afd3b2cbc875aa4792c1fba
Link: https://lkml.kernel.org/r/20220427195820.1716975-1-pcc@google.com
Signed-off-by: Peter Collingbourne <pcc@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13 07:20:07 -07:00
Alexei Starovoitov 4b6313cf99 bpf: Fix combination of jit blinding and pointers to bpf subprogs.
The combination of jit blinding and pointers to bpf subprogs causes:
[   36.989548] BUG: unable to handle page fault for address: 0000000100000001
[   36.990342] #PF: supervisor instruction fetch in kernel mode
[   36.990968] #PF: error_code(0x0010) - not-present page
[   36.994859] RIP: 0010:0x100000001
[   36.995209] Code: Unable to access opcode bytes at RIP 0xffffffd7.
[   37.004091] Call Trace:
[   37.004351]  <TASK>
[   37.004576]  ? bpf_loop+0x4d/0x70
[   37.004932]  ? bpf_prog_3899083f75e4c5de_F+0xe3/0x13b

The jit blinding logic didn't recognize that ld_imm64 with an address
of bpf subprogram is a special instruction and proceeded to randomize it.
By itself it wouldn't have been an issue, but jit_subprogs() logic
relies on two step process to JIT all subprogs and then JIT them
again when addresses of all subprogs are known.
Blinding process in the first JIT phase caused second JIT to miss
adjustment of special ld_imm64.

Fix this issue by ignoring special ld_imm64 instructions that don't have
user controlled constants and shouldn't be blinded.

Fixes: 69c087ba62 ("bpf: Add bpf_for_each_map_elem() helper")
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220513011025.13344-1-alexei.starovoitov@gmail.com
2022-05-13 15:13:48 +02:00
Christoph Hellwig 1b8e5d1a53 swiotlb: use the right nslabs-derived sizes in swiotlb_init_late
nslabs can shrink when allocations or the remap don't succeed, so make
sure to use it for all sizing.  For that remove the bytes value that
can get stale and replace it with local calculations and a boolean to
indicate if the originally requested size could not be allocated.

Fixes: 6424e31b1c ("swiotlb: remove swiotlb_init_with_tbl and swiotlb_init_late_with_tbl")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2022-05-13 12:49:27 +02:00
Christoph Hellwig a5e891321a swiotlb: use the right nslabs value in swiotlb_init_remap
default_nslabs should only be used to initialize nslabs, after that we
need to use the local variable that can shrink when allocations or the
remap don't succeed.

Fixes: 6424e31b1c ("swiotlb: remove swiotlb_init_with_tbl and swiotlb_init_late_with_tbl")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2022-05-13 12:49:18 +02:00
Christoph Hellwig 1521c607ca swiotlb: don't panic when the swiotlb buffer can't be allocated
For historical reasons the switlb code paniced when the metadata could
not be allocated, but just printed a warning when the actual main
swiotlb buffer could not be allocated.  Restore this somewhat unexpected
behavior as changing it caused a boot failure on the Microchip RISC-V
PolarFire SoC Icicle kit.

Fixes: 6424e31b1c ("swiotlb: remove swiotlb_init_with_tbl and swiotlb_init_late_with_tbl")
Reported-by: Conor Dooley <Conor.Dooley@microchip.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Conor Dooley <Conor.Dooley@microchip.com>
2022-05-13 12:48:58 +02:00
Sebastian Andrzej Siewior 6829061315 futex: Remove a PREEMPT_RT_FULL reference.
Earlier the PREEMPT_RT patch had a PREEMPT_RT_FULL and PREEMPT_RT_BASE
Kconfig option. The latter was a subset of the functionality that was
enabled with PREEMPT_RT_FULL and was mainly useful for debugging.

During the merging efforts the two Kconfig options were abandoned in the
v5.4.3-rt1 release and since then there is only PREEMPT_RT which enables
the full features set (as PREEMPT_RT_FULL did in earlier releases).

Replace the PREEMPT_RT_FULL reference with PREEMPT_RT.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/YnvWUvq1vpqCfCU7@linutronix.de
2022-05-13 12:36:51 +02:00
Colin Ian King 47b7eae62a relay: remove redundant assignment to pointer buf
Pointer buf is being assigned a value that is not being read, buf is being
re-assigned in the next starement.  The assignment is redundant and can be
removed.

Cleans up clang scan build warning:
kernel/relay.c:443:8: warning: Although the value stored to 'buf' is
used in the enclosing expression, the value is never actually read
from 'buf' [deadcode.DeadStores]

Link: https://lkml.kernel.org/r/20220508212152.58753-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-12 20:38:37 -07:00
lizhe a7bd57b87f kernel/crash_core.c: remove redundant check of ck_cmdline
At the end of get_last_crashkernel(), the judgement of ck_cmdline is
obviously unnecessary and causes redundance, let's clean it up.

Link: https://lkml.kernel.org/r/20220506104116.259323-1-sensor1010@163.com
Signed-off-by: lizhe <sensor1010@163.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Philipp Rudo <prudo@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-12 20:38:36 -07:00
Jakub Kicinski 9b19e57a3c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts.

Build issue in drivers/net/ethernet/sfc/ptp.c
  54fccfdd7c ("sfc: efx_default_channel_type APIs can be static")
  49e6123c65 ("net: sfc: fix memory leak due to ptp channel")
https://lore.kernel.org/all/20220510130556.52598fe2@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-12 16:15:30 -07:00
Linus Torvalds 0ac824f379 Merge branch 'for-5.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
 "Waiman's fix for a cgroup2 cpuset bug where it could miss nodes which
  were hot-added"

* 'for-5.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp()
2022-05-12 10:42:56 -07:00
Masahiro Yamada 7390b94a3c module: merge check_exported_symbol() into find_exported_symbol_in_section()
Now check_exported_symbol() always succeeds.

Merge it into find_exported_symbol_in_search() to make the code concise.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Masahiro Yamada cdd66eb52f module: do not binary-search in __ksymtab_gpl if fsa->gplok is false
Currently, !fsa->gplok && syms->license == GPL_ONLY) is checked after
bsearch() succeeds.

It is meaningless to do the binary search in the GPL symbol table when
fsa->gplok is false because we know find_exported_symbol_in_section()
will fail anyway.

This check should be done before bsearch().

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Masahiro Yamada c6eee9df57 module: do not pass opaque pointer for symbol search
There is no need to use an opaque pointer for check_exported_symbol()
or find_exported_symbol_in_section.

Pass (struct find_symbol_arg *) explicitly.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Lecopzer Chen 8eac910a49 module: show disallowed symbol name for inherit_taint()
The error log for inherit_taint() doesn't really help to find the
symbol which violates GPL rules.

For example,
if a module has 300 symbol and includes 50 disallowed symbols,
the log only shows the content below and we have no idea what symbol is.
    AAA: module using GPL-only symbols uses symbols from proprietary module BBB.

It's hard for user who doesn't really know how the symbol was parsing.

This patch add symbol name to tell the offending symbols explicitly.
    AAA: module using GPL-only symbols uses symbols SSS from proprietary module BBB.

Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Alexey Dobriyan 391e982bfa module: fix [e_shstrndx].sh_size=0 OOB access
It is trivial to craft a module to trigger OOB access in this line:

	if (info->secstrings[strhdr->sh_size - 1] != '\0') {

BUG: unable to handle page fault for address: ffffc90000aa0fff
PGD 100000067 P4D 100000067 PUD 100066067 PMD 10436f067 PTE 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 7 PID: 1215 Comm: insmod Not tainted 5.18.0-rc5-00007-g9bf578647087-dirty #10
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-4.fc34 04/01/2014
RIP: 0010:load_module+0x19b/0x2391

Fixes: ec2a29593c ("module: harden ELF info handling")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
[rebased patch onto modules-next]
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Aaron Tomlin 99bd995655 module: Introduce module unload taint tracking
Currently, only the initial module that tainted the kernel is
recorded e.g. when an out-of-tree module is loaded.

The purpose of this patch is to allow the kernel to maintain a record of
each unloaded module that taints the kernel. So, in addition to
displaying a list of linked modules (see print_modules()) e.g. in the
event of a detected bad page, unloaded modules that carried a taint/or
taints are displayed too. A tainted module unload count is maintained.

The number of tracked modules is not fixed. This feature is disabled by
default.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Aaron Tomlin 6fb0538d01 module: Move module_assert_mutex_or_preempt() to internal.h
No functional change.

This patch migrates module_assert_mutex_or_preempt() to internal.h.
So, the aforementiond function can be used outside of main/or core
module code yet will remain restricted for internal use only.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Aaron Tomlin c14e522bc7 module: Make module_flags_taint() accept a module's taints bitmap and usable outside core code
No functional change.

The purpose of this patch is to modify module_flags_taint() to accept
a module's taints bitmap as a parameter and modifies all users
accordingly. Furthermore, it is now possible to access a given
module's taint flags data outside of non-essential code yet does
remain for internal use only.

This is in preparation for module unload taint tracking support.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-12 10:29:41 -07:00
Peter Zijlstra 2760f5a415 stop_machine: Add stop_core_cpuslocked() for per-core operations
Hardware core level testing features require near simultaneous execution
of WRMSR instructions on all threads of a core to initiate a test.

Provide a customized cut down version of stop_machine_cpuslocked() that
just operates on the threads of a single core.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220506225410.1652287-4-tony.luck@intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2022-05-12 15:35:29 +02:00
Yuntao Wang a2aa95b71c bpf: Fix potential array overflow in bpf_trampoline_get_progs()
The cnt value in the 'cnt >= BPF_MAX_TRAMP_PROGS' check does not
include BPF_TRAMP_MODIFY_RETURN bpf programs, so the number of
the attached BPF_TRAMP_MODIFY_RETURN bpf programs in a trampoline
can exceed BPF_MAX_TRAMP_PROGS.

When this happens, the assignment '*progs++ = aux->prog' in
bpf_trampoline_get_progs() will cause progs array overflow as the
progs field in the bpf_tramp_progs struct can only hold at most
BPF_MAX_TRAMP_PROGS bpf programs.

Fixes: 88fd9e5352 ("bpf: Refactor trampoline update code")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Link: https://lore.kernel.org/r/20220430130803.210624-1-ytcoode@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-11 21:24:20 -07:00
Feng Zhou 07343110b2 bpf: add bpf_map_lookup_percpu_elem for percpu map
Add new ebpf helpers bpf_map_lookup_percpu_elem.

The implementation method is relatively simple, refer to the implementation
method of map_lookup_elem of percpu map, increase the parameters of cpu, and
obtain it according to the specified cpu.

Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Link: https://lore.kernel.org/r/20220511093854.411-2-zhoufeng.zf@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-11 18:16:54 -07:00
Delyan Kratunov 9c2136be08 sched/tracing: Append prev_state to tp args instead
Commit fa2c3254d7 (sched/tracing: Don't re-read p->state when emitting
sched_switch event, 2022-01-20) added a new prev_state argument to the
sched_switch tracepoint, before the prev task_struct pointer.

This reordering of arguments broke BPF programs that use the raw
tracepoint (e.g. tp_btf programs). The type of the second argument has
changed and existing programs that assume a task_struct* argument
(e.g. for bpf_task_storage access) will now fail to verify.

If we instead append the new argument to the end, all existing programs
would continue to work and can conditionally extract the prev_state
argument on supported kernel versions.

Fixes: fa2c3254d7 (sched/tracing: Don't re-read p->state when emitting sched_switch event, 2022-01-20)
Signed-off-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lkml.kernel.org/r/c8a6930dfdd58a4a5755fc01732675472979732b.camel@fb.com
2022-05-12 00:37:11 +02:00
Peter Zijlstra 31cae1eaae sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state
Currently ptrace_stop() / do_signal_stop() rely on the special states
TASK_TRACED and TASK_STOPPED resp. to keep unique state. That is, this
state exists only in task->__state and nowhere else.

There's two spots of bother with this:

 - PREEMPT_RT has task->saved_state which complicates matters,
   meaning task_is_{traced,stopped}() needs to check an additional
   variable.

 - An alternative freezer implementation that itself relies on a
   special TASK state would loose TASK_TRACED/TASK_STOPPED and will
   result in misbehaviour.

As such, add additional state to task->jobctl to track this state
outside of task->__state.

NOTE: this doesn't actually fix anything yet, just adds extra state.

--EWB
  * didn't add a unnecessary newline in signal.h
  * Update t->jobctl in signal_wake_up and ptrace_signal_wake_up
    instead of in signal_wake_up_state.  This prevents the clearing
    of TASK_STOPPED and TASK_TRACED from getting lost.
  * Added warnings if JOBCTL_STOPPED or JOBCTL_TRACED are not cleared

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220421150654.757693825@infradead.org
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-12-ebiederm@xmission.com
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2022-05-11 14:37:06 -05:00
Eric W. Biederman 5b4197cb28 ptrace: Always take siglock in ptrace_resume
Make code analysis simpler and future changes easier by
always taking siglock in ptrace_resume.

Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-11-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:36:30 -05:00
Eric W. Biederman 2500ad1c7f ptrace: Don't change __state
Stop playing with tsk->__state to remove TASK_WAKEKILL while a ptrace
command is executing.

Instead remove TASK_WAKEKILL from the definition of TASK_TRACED, and
implement a new jobctl flag TASK_PTRACE_FROZEN.  This new flag is set
in jobctl_freeze_task and cleared when ptrace_stop is awoken or in
jobctl_unfreeze_task (when ptrace_stop remains asleep).

In signal_wake_up add __TASK_TRACED to state along with TASK_WAKEKILL
when the wake up is for a fatal signal.  Skip adding __TASK_TRACED
when TASK_PTRACE_FROZEN is not set.  This has the same effect as
changing TASK_TRACED to __TASK_TRACED as all of the wake_ups that use
TASK_KILLABLE go through signal_wake_up.

Handle a ptrace_stop being called with a pending fatal signal.
Previously it would have been handled by schedule simply failing to
sleep.  As TASK_WAKEKILL is no longer part of TASK_TRACED schedule
will sleep with a fatal_signal_pending.   The code in signal_wake_up
guarantees that the code will be awaked by any fatal signal that
codes after TASK_TRACED is set.

Previously the __state value of __TASK_TRACED was changed to
TASK_RUNNING when woken up or back to TASK_TRACED when the code was
left in ptrace_stop.  Now when woken up ptrace_stop now clears
JOBCTL_PTRACE_FROZEN and when left sleeping ptrace_unfreezed_traced
clears JOBCTL_PTRACE_FROZEN.

Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-10-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:35:32 -05:00
Eric W. Biederman 57b6de08b5 ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs
Long ago and far away there was a BUG_ON at the start of ptrace_stop
that did "BUG_ON(!(current->ptrace & PT_PTRACED));" [1].  The BUG_ON
had never triggered but examination of the code showed that the BUG_ON
could actually trigger.  To complement removing the BUG_ON an attempt
to better handle the race was added.

The code detected the tracer had gone away and did not call
do_notify_parent_cldstop.  The code also attempted to prevent
ptrace_report_syscall from sending spurious SIGTRAPs when the tracer
went away.

The code to detect when the tracer had gone away before sending a
signal to tracer was a legitimate fix and continues to work to this
date.

The code to prevent sending spurious SIGTRAPs is a failure.  At the
time and until today the code only catches it when the tracer goes
away after siglock is dropped and before read_lock is acquired.  If
the tracer goes away after read_lock is dropped a spurious SIGTRAP can
still be sent to the tracee.  The tracer going away after read_lock
is dropped is the far likelier case as it is the bigger window.

Given that the attempt to prevent the generation of a SIGTRAP was a
failure and continues to be a failure remove the code that attempts to
do that.  This simplifies the code in ptrace_stop and makes
ptrace_stop much easier to reason about.

To successfully deal with the tracer going away, all of the tracer's
instrumentation of the child would need to be removed, and reliably
detecting when the tracer has set a signal to continue with would need
to be implemented.

[1] 66519f549ae5 ("[PATCH] fix ptracer death race yielding bogus BUG_ON")
History-Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-9-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:35:00 -05:00
Eric W. Biederman 7b0fe1367e ptrace: Document that wait_task_inactive can't fail
After ptrace_freeze_traced succeeds it is known that the tracee
has a __state value of __TASK_TRACED and that no __ptrace_unlink will
happen because the tracer is waiting for the tracee, and the tracee is
in ptrace_stop.

The function ptrace_freeze_traced can succeed at any point after
ptrace_stop has set TASK_TRACED and dropped siglock.  The read_lock on
tasklist_lock only excludes ptrace_attach.

This means that the !current->ptrace which executes under a read_lock
of tasklist_lock will never see a ptrace_freeze_trace as the tracer
must have gone away before the tasklist_lock was taken and
ptrace_attach can not occur until the read_lock is dropped.  As
ptrace_freeze_traced depends upon ptrace_attach running before it can
run that excludes ptrace_freeze_traced until __state is set to
TASK_RUNNING.  This means that task_is_traced will fail in
ptrace_freeze_attach and ptrace_freeze_attached will fail.

On the current->ptrace branch of ptrace_stop which will be reached any
time after ptrace_freeze_traced has succeed it is known that __state
is __TASK_TRACED and schedule() will be called with that state.

Use a WARN_ON_ONCE to document that wait_task_inactive(TASK_TRACED)
should never fail.  Remove the stale comment about may_ptrace_stop.

Strictly speaking this is not true because if PREEMPT_RT is enabled
wait_task_inactive can fail because __state can be changed.  I don't
see this as a problem as the ptrace code is currently broken on
PREMPT_RT, and this is one of the issues.  Failing and warning when
the assumptions of the code are broken is good.

Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-8-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:34:47 -05:00
Eric W. Biederman 6a2d90ba02 ptrace: Reimplement PTRACE_KILL by always sending SIGKILL
The current implementation of PTRACE_KILL is buggy and has been for
many years as it assumes it's target has stopped in ptrace_stop.  At a
quick skim it looks like this assumption has existed since ptrace
support was added in linux v1.0.

While PTRACE_KILL has been deprecated we can not remove it as
a quick search with google code search reveals many existing
programs calling it.

When the ptracee is not stopped at ptrace_stop some fields would be
set that are ignored except in ptrace_stop.  Making the userspace
visible behavior of PTRACE_KILL a noop in those case.

As the usual rules are not obeyed it is not clear what the
consequences are of calling PTRACE_KILL on a running process.
Presumably userspace does not do this as it achieves nothing.

Replace the implementation of PTRACE_KILL with a simple
send_sig_info(SIGKILL) followed by a return 0.  This changes the
observable user space behavior only in that PTRACE_KILL on a process
not stopped in ptrace_stop will also kill it.  As that has always
been the intent of the code this seems like a reasonable change.

Cc: stable@vger.kernel.org
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-7-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:34:28 -05:00
Eric W. Biederman cb3c19c93d signal: Use lockdep_assert_held instead of assert_spin_locked
The distinction is that assert_spin_locked() checks if the lock is
held *by*anyone* whereas lockdep_assert_held() asserts the current
context holds the lock.  Also, the check goes away if you build
without lockdep.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/Ympr/+PX4XgT/UKU@hirez.programming.kicks-ass.net
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-6-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:34:14 -05:00
Eric W. Biederman 16cc1bc67d ptrace: Remove arch_ptrace_attach
The last remaining implementation of arch_ptrace_attach is ia64's
ptrace_attach_sync_user_rbs which was added at the end of 2007 in
commit aa91a2e900 ("[IA64] Synchronize RBS on PTRACE_ATTACH").

Reading the comments and examining the code ptrace_attach_sync_user_rbs
has the sole purpose of saving registers to the stack when ptrace_attach
changes TASK_STOPPED to TASK_TRACED.  In all other cases arch_ptrace_stop
takes care of the register saving.

In commit d79fdd6d96 ("ptrace: Clean transitions between TASK_STOPPED and TRACED")
modified ptrace_attach to wake up the thread and enter ptrace_stop normally even
when the thread starts out stopped.

This makes ptrace_attach_sync_user_rbs completely unnecessary.  So just
remove it.

I read through the code to verify that ptrace_attach_sync_user_rbs is
unnecessary.  What I found is that the code is quite dead.

Reading ptrace_attach_sync_user_rbs it is easy to see that the it does
nothing unless __state == TASK_STOPPED.

Calling arch_ptrace_attach (aka ptrace_attach_sync_user_rbs) after
ptrace_traceme it is easy to see that because we are talking about the
current process the value of __state is TASK_RUNNING.  Which means
ptrace_attach_sync_user_rbs does nothing.

The only other call of arch_ptrace_attach (aka
ptrace_attach_sync_user_rbs) is after ptrace_attach.

If the task is running (and PTRACE_SEIZE is not specified), a SIGSTOP
is sent which results in do_signal_stop setting JOBCTL_TRAP_STOP on
the target task (as it is ptraced) and the target task stopping
in ptrace_stop with __state == TASK_TRACED.

If the task was already stopped then ptrace_attach sets
JOBCTL_TRAPPING and JOBCTL_TRAP_STOP, wakes it out of __TASK_STOPPED,
and waits until the JOBCTL_TRAPPING_BIT is clear.  At which point
the task stops in ptrace_stop.

In both cases there are a couple of funning excpetions such as if the
traced task receiveds a SIGCONT, or is set a fatal signal.

However in all of those cases the tracee never stops in __state
TASK_STOPPED.  Which is a long way of saying that ptrace_attach_sync_user_rbs
is guaranteed never to do anything.

Cc: linux-ia64@vger.kernel.org
Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:33:54 -05:00
Eric W. Biederman e71ba12407 signal: Replace __group_send_sig_info with send_signal_locked
The function __group_send_sig_info is just a light wrapper around
send_signal_locked with one parameter fixed to a constant value.  As
the wrapper adds no real value update the code to directly call the
wrapped function.

Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-2-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:33:17 -05:00
Eric W. Biederman 157cc18122 signal: Rename send_signal send_signal_locked
Rename send_signal and __send_signal to send_signal_locked and
__send_signal_locked to make send_signal usable outside of
signal.c.

Tested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20220505182645.497868-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 14:32:57 -05:00
Paul E. McKenney ce13389053 Merge branch 'exp.2022.05.11a' into HEAD
exp.2022.05.11a: Expedited-grace-period latency-reduction updates.
2022-05-11 11:49:35 -07:00
Kalesh Singh 9621fbee44 rcu: Move expedited grace period (GP) work to RT kthread_worker
Enabling CONFIG_RCU_BOOST did not reduce RCU expedited grace-period
latency because its workqueues run at SCHED_OTHER, and thus can be
delayed by normal processes.  This commit avoids these delays by moving
the expedited GP work items to a real-time-priority kthread_worker.

This option is controlled by CONFIG_RCU_EXP_KTHREAD and disabled by
default on PREEMPT_RT=y kernels which disable expedited grace periods
after boot by unconditionally setting rcupdate.rcu_normal_after_boot=1.

The results were evaluated on arm64 Android devices (6GB ram) running
5.10 kernel, and capturing trace data in critical user-level code.

The table below shows the resulting order-of-magnitude improvements
in synchronize_rcu_expedited() latency:

------------------------------------------------------------------------
|                          |   workqueues  |  kthread_worker |  Diff   |
------------------------------------------------------------------------
| Count                    |          725  |            688  |         |
------------------------------------------------------------------------
| Min Duration       (ns)  |          326  |            447  |  37.12% |
------------------------------------------------------------------------
| Q1                 (ns)  |       39,428  |         38,971  |  -1.16% |
------------------------------------------------------------------------
| Q2 - Median        (ns)  |       98,225  |         69,743  | -29.00% |
------------------------------------------------------------------------
| Q3                 (ns)  |      342,122  |        126,638  | -62.98% |
------------------------------------------------------------------------
| Max Duration       (ns)  |  372,766,967  |      2,329,671  | -99.38% |
------------------------------------------------------------------------
| Avg Duration       (ns)  |    2,746,353  |        151,242  | -94.49% |
------------------------------------------------------------------------
| Standard Deviation (ns)  |   19,327,765  |        294,408  |         |
------------------------------------------------------------------------

The below table show the range of maximums/minimums for
synchronize_rcu_expedited() latency from all experiments:

------------------------------------------------------------------------
|                          |   workqueues  |  kthread_worker |  Diff   |
------------------------------------------------------------------------
| Total No. of Experiments |           25  |             23  |         |
------------------------------------------------------------------------
| Largest  Maximum   (ns)  |  372,766,967  |      2,329,671  | -99.38% |
------------------------------------------------------------------------
| Smallest Maximum   (ns)  |       38,819  |         86,954  | 124.00% |
------------------------------------------------------------------------
| Range of Maximums  (ns)  |  372,728,148  |      2,242,717  |         |
------------------------------------------------------------------------
| Largest  Minimum   (ns)  |       88,623  |         27,588  | -68.87% |
------------------------------------------------------------------------
| Smallest Minimum   (ns)  |          326  |            447  |  37.12% |
------------------------------------------------------------------------
| Range of Minimums  (ns)  |       88,297  |         27,141  |         |
------------------------------------------------------------------------

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Reported-by: Tim Murray <timmurray@google.com>
Reported-by: Wei Wang <wvw@google.com>
Tested-by: Kyle Lin <kylelin@google.com>
Tested-by: Chunwei Lu <chunweilu@google.com>
Tested-by: Lulu Wang <luluw@google.com>
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-05-11 11:47:10 -07:00
Uladzislau Rezki 28b3ae4265 rcu: Introduce CONFIG_RCU_EXP_CPU_STALL_TIMEOUT
Currently both expedited and regular grace period stall warnings use
a single timeout value that with units of seconds.  However, recent
Android use cases problem require a sub-100-millisecond expedited RCU CPU
stall warning.  Given that expedited RCU grace periods normally complete
in far less than a single millisecond, especially for small systems,
this is not unreasonable.

Therefore introduce the CONFIG_RCU_EXP_CPU_STALL_TIMEOUT kernel
configuration that defaults to 20 msec on Android and remains the same
as that of the non-expedited stall warnings otherwise.  It also can be
changed in run-time via: /sys/.../parameters/rcu_exp_cpu_stall_timeout.

[ paulmck: Default of zero to use CONFIG_RCU_STALL_TIMEOUT. ]

Signed-off-by: Uladzislau Rezki <uladzislau.rezki@sony.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-05-11 11:38:50 -07:00
Mikulas Patocka 84bc4f1dbb dma-debug: change allocation mode from GFP_NOWAIT to GFP_ATIOMIC
We observed the error "cacheline tracking ENOMEM, dma-debug disabled"
during a light system load (copying some files). The reason for this error
is that the dma_active_cacheline radix tree uses GFP_NOWAIT allocation -
so it can't access the emergency memory reserves and it fails as soon as
anybody reaches the watermark.

This patch changes GFP_NOWAIT to GFP_ATOMIC, so that it can access the
emergency memory reserves.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-05-11 19:48:34 +02:00
Christoph Hellwig 92826e9675 dma-direct: don't fail on highmem CMA pages in dma_direct_alloc_pages
When dma_direct_alloc_pages encounters a highmem page it just gives up
currently.  But what we really should do is to try memory using the
page allocator instead - without this platforms with a global highmem
CMA pool will fail all dma_alloc_pages allocations.

Fixes: efa70f2fdc ("dma-mapping: add a new dma_alloc_pages API")
Reported-by: Mark O'Neill <mao@tumblingdice.co.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2022-05-11 19:48:34 +02:00
Eric W. Biederman b3f9916d81 sched: Update task_tick_numa to ignore tasks without an mm
Qian Cai <quic_qiancai@quicinc.com> wrote:
> Reverting the last 3 commits of the series fixed a boot crash.
>
> 1b2552cbdb fork: Stop allowing kthreads to call execve
> 753550eb0c fork: Explicitly set PF_KTHREAD
> 68d85f0a33 init: Deal with the init process being a user mode process
>
>  BUG: KASAN: null-ptr-deref in task_nr_scan_windows.isra.0
>  arch_atomic_long_read at ./include/linux/atomic/atomic-long.h:29
>  (inlined by) atomic_long_read at ./include/linux/atomic/atomic-instrumented.h:1266
>  (inlined by) get_mm_counter at ./include/linux/mm.h:1996
>  (inlined by) get_mm_rss at ./include/linux/mm.h:2049
>  (inlined by) task_nr_scan_windows at kernel/sched/fair.c:1123
>  Read of size 8 at addr 00000000000003d0 by task swapper/0/1

With the change to init and the user mode helper processes to not have
PF_KTHREAD set before they call kernel_execve the PF_KTHREAD test in
task_tick_numa became insufficient to detect all tasks that have
"->mm == NULL".  Correct that by testing for "->mm == NULL" directly.

Reported-by: Qian Cai <quic_qiancai@quicinc.com>
Tested-by: Qian Cai <quic_qiancai@quicinc.com>
Fixes: 1b2552cbdb ("fork: Stop allowing kthreads to call execve")
Link: https://lkml.kernel.org/r/87r150ug1l.fsf_-_@email.froward.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-11 12:41:48 -05:00
Pierre Gondois c9d8923bfb PM: EM: Decrement policy counter
In commit e458716a92 ("PM: EM: Mark inefficiencies in CPUFreq"),
cpufreq_cpu_get() is called without a cpufreq_cpu_put(), permanently
increasing the reference counts of the policy struct.

Decrement the reference count once the policy struct is not used
anymore.

Fixes: e458716a92 ("PM: EM: Mark inefficiencies in CPUFreq")
Tested-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Reviewed-by: Vincent Donnefort <vincent.donnefort@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-05-11 19:15:14 +02:00
Hao Jia 734387ec2f sched/deadline: Remove superfluous rq clock update in push_dl_task()
The change to call update_rq_clock() before activate_task()
commit 840d719604 ("sched/deadline: Update rq_clock of later_rq
when pushing a task") is no longer needed since commit f4904815f9
("sched/deadline: Fix double accounting of rq/running bw in push & pull")
removed the add_running_bw() before the activate_task().

So we remove some comments that are no longer needed and update
rq clock in activate_task().

Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lore.kernel.org/r/20220430085843.62939-3-jiahao.os@bytedance.com
2022-05-11 16:27:12 +02:00
Hao Jia 2679a83731 sched/core: Avoid obvious double update_rq_clock warning
When we use raw_spin_rq_lock() to acquire the rq lock and have to
update the rq clock while holding the lock, the kernel may issue
a WARN_DOUBLE_CLOCK warning.

Since we directly use raw_spin_rq_lock() to acquire rq lock instead of
rq_lock(), there is no corresponding change to rq->clock_update_flags.
In particular, we have obtained the rq lock of other CPUs, the
rq->clock_update_flags of this CPU may be RQCF_UPDATED at this time, and
then calling update_rq_clock() will trigger the WARN_DOUBLE_CLOCK warning.

So we need to clear RQCF_UPDATED of rq->clock_update_flags to avoid
the WARN_DOUBLE_CLOCK warning.

For the sched_rt_period_timer() and migrate_task_rq_dl() cases
we simply replace raw_spin_rq_lock()/raw_spin_rq_unlock() with
rq_lock()/rq_unlock().

For the {pull,push}_{rt,dl}_task() cases, we add the
double_rq_clock_clear_update() function to clear RQCF_UPDATED of
rq->clock_update_flags, and call double_rq_clock_clear_update()
before double_lock_balance()/double_rq_lock() returns to avoid the
WARN_DOUBLE_CLOCK warning.

Some call trace reports:
Call Trace 1:
 <IRQ>
 sched_rt_period_timer+0x10f/0x3a0
 ? enqueue_top_rt_rq+0x110/0x110
 __hrtimer_run_queues+0x1a9/0x490
 hrtimer_interrupt+0x10b/0x240
 __sysvec_apic_timer_interrupt+0x8a/0x250
 sysvec_apic_timer_interrupt+0x9a/0xd0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20

Call Trace 2:
 <TASK>
 activate_task+0x8b/0x110
 push_rt_task.part.108+0x241/0x2c0
 push_rt_tasks+0x15/0x30
 finish_task_switch+0xaa/0x2e0
 ? __switch_to+0x134/0x420
 __schedule+0x343/0x8e0
 ? hrtimer_start_range_ns+0x101/0x340
 schedule+0x4e/0xb0
 do_nanosleep+0x8e/0x160
 hrtimer_nanosleep+0x89/0x120
 ? hrtimer_init_sleeper+0x90/0x90
 __x64_sys_nanosleep+0x96/0xd0
 do_syscall_64+0x34/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Call Trace 3:
 <TASK>
 deactivate_task+0x93/0xe0
 pull_rt_task+0x33e/0x400
 balance_rt+0x7e/0x90
 __schedule+0x62f/0x8e0
 do_task_dead+0x3f/0x50
 do_exit+0x7b8/0xbb0
 do_group_exit+0x2d/0x90
 get_signal+0x9df/0x9e0
 ? preempt_count_add+0x56/0xa0
 ? __remove_hrtimer+0x35/0x70
 arch_do_signal_or_restart+0x36/0x720
 ? nanosleep_copyout+0x39/0x50
 ? do_nanosleep+0x131/0x160
 ? audit_filter_inodes+0xf5/0x120
 exit_to_user_mode_prepare+0x10f/0x1e0
 syscall_exit_to_user_mode+0x17/0x30
 do_syscall_64+0x40/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Call Trace 4:
 update_rq_clock+0x128/0x1a0
 migrate_task_rq_dl+0xec/0x310
 set_task_cpu+0x84/0x1e4
 try_to_wake_up+0x1d8/0x5c0
 wake_up_process+0x1c/0x30
 hrtimer_wakeup+0x24/0x3c
 __hrtimer_run_queues+0x114/0x270
 hrtimer_interrupt+0xe8/0x244
 arch_timer_handler_phys+0x30/0x50
 handle_percpu_devid_irq+0x88/0x140
 generic_handle_domain_irq+0x40/0x60
 gic_handle_irq+0x48/0xe0
 call_on_irq_stack+0x2c/0x60
 do_interrupt_handler+0x80/0x84

Steps to reproduce:
1. Enable CONFIG_SCHED_DEBUG when compiling the kernel
2. echo 1 > /sys/kernel/debug/clear_warn_once
   echo "WARN_DOUBLE_CLOCK" > /sys/kernel/debug/sched/features
   echo "NO_RT_PUSH_IPI" > /sys/kernel/debug/sched/features
3. Run some rt/dl tasks that periodically work and sleep, e.g.
Create 2*n rt or dl (90% running) tasks via rt-app (on a system
with n CPUs), and Dietmar Eggemann reports Call Trace 4 when running
on PREEMPT_RT kernel.

Signed-off-by: Hao Jia <jiahao.os@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20220430085843.62939-2-jiahao.os@bytedance.com
2022-05-11 16:27:11 +02:00
Peter Zijlstra 47319846a9 Linux 5.18-rc5
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Merge branch 'v5.18-rc5'

Obtain the new INTEL_FAM6 stuff required.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
2022-05-11 16:27:06 +02:00
Waiman Long 434e09e757 locking/qrwlock: Change "queue rwlock" to "queued rwlock"
Queued rwlock was originally named "queue rwlock" which wasn't quite
grammatically correct. However there are still some "queue rwlock"
references in the code. Change those to "queued rwlock" for consistency.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220510192134.434753-1-longman@redhat.com
2022-05-11 16:27:04 +02:00
Kui-Feng Lee 2fcc82411e bpf, x86: Attach a cookie to fentry/fexit/fmod_ret/lsm.
Pass a cookie along with BPF_LINK_CREATE requests.

Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie.
The cookie of a bpf_tracing_link is available by calling
bpf_get_attach_cookie when running the BPF program of the attached
link.

The value of a cookie will be set at bpf_tramp_run_ctx by the
trampoline of the link.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-4-kuifeng@fb.com
2022-05-10 21:58:31 -07:00
Kui-Feng Lee e384c7b7b4 bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack
BPF trampolines will create a bpf_tramp_run_ctx, a bpf_run_ctx, on
stacks and set/reset the current bpf_run_ctx before/after calling a
bpf_prog.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-3-kuifeng@fb.com
2022-05-10 17:50:51 -07:00
Kui-Feng Lee f7e0beaf39 bpf, x86: Generate trampolines from bpf_tramp_links
Replace struct bpf_tramp_progs with struct bpf_tramp_links to collect
struct bpf_tramp_link(s) for a trampoline.  struct bpf_tramp_link
extends bpf_link to act as a linked list node.

arch_prepare_bpf_trampoline() accepts a struct bpf_tramp_links to
collects all bpf_tramp_link(s) that a trampoline should call.

Change BPF trampoline and bpf_struct_ops to pass bpf_tramp_links
instead of bpf_tramp_progs.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220510205923.3206889-2-kuifeng@fb.com
2022-05-10 17:50:40 -07:00
Lukas Wunner 792ea6a074 genirq: Remove WARN_ON_ONCE() in generic_handle_domain_irq()
Since commit 0953fb2637 ("irq: remove handle_domain_{irq,nmi}()"),
generic_handle_domain_irq() warns if called outside hardirq context, even
though the function calls down to handle_irq_desc(), which warns about the
same, but conditionally on handle_enforce_irqctx().

The newly added warning is a false positive if the interrupt originates
from any other irqchip than x86 APIC or ARM GIC/GICv3.  Those are the only
ones for which handle_enforce_irqctx() returns true.  Per commit
c16816acd0 ("genirq: Add protection against unsafe usage of
generic_handle_irq()"):

 "In general calling generic_handle_irq() with interrupts disabled from non
  interrupt context is harmless. For some interrupt controllers like the
  x86 trainwrecks this is outright dangerous as it might corrupt state if
  an interrupt affinity change is pending."

Examples for interrupt chips where the warning is a false positive are
USB-attached GPIO controllers such as drivers/gpio/gpio-dln2.c:

  USB gadgets are incapable of directly signaling an interrupt because they
  cannot initiate a bus transaction by themselves.  All communication on
  the bus is initiated by the host controller, which polls a gadget's
  Interrupt Endpoint in regular intervals.  If an interrupt is pending,
  that information is passed up the stack in softirq context, from which a
  hardirq is synthesized via generic_handle_domain_irq().

Remove the warning to eliminate such false positives.

Fixes: 0953fb2637 ("irq: remove handle_domain_{irq,nmi}()")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Jakub Kicinski <kuba@kernel.org>
CC: Linus Walleij <linus.walleij@linaro.org>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Octavian Purdila <octavian.purdila@nxp.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220505113207.487861b2@kernel.org
Link: https://lore.kernel.org/r/20220506203242.GA1855@wunner.de
Link: https://lore.kernel.org/r/c3caf60bfa78e5fdbdf483096b7174da65d1813a.1652168866.git.lukas@wunner.de
2022-05-11 02:22:52 +02:00
Jiri Olsa 0236fec57a bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link
Using kallsyms_lookup_names function to speed up symbols lookup in
kprobe multi link attachment and replacing with it the current
kprobe_multi_resolve_syms function.

This speeds up bpftrace kprobe attachment:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  6.5681 +- 0.0225 seconds time elapsed  ( +-  0.34% )

After:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  0.5661 +- 0.0275 seconds time elapsed  ( +-  4.85% )

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-10 14:42:06 -07:00
Jiri Olsa 8be9253344 fprobe: Resolve symbols with ftrace_lookup_symbols
Using ftrace_lookup_symbols to speed up symbols lookup
in register_fprobe_syms API.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-4-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-10 14:42:06 -07:00
Jiri Olsa bed0d9a50d ftrace: Add ftrace_lookup_symbols function
Adding ftrace_lookup_symbols function that resolves array of symbols
with single pass over kallsyms.

The user provides array of string pointers with count and pointer to
allocated array for resolved values.

  int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt,
                            unsigned long *addrs)

It iterates all kallsyms symbols and tries to loop up each in provided
symbols array with bsearch. The symbols array needs to be sorted by
name for this reason.

We also check each symbol to pass ftrace_location, because this API
will be used for fprobe symbols resolving.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-10 14:42:06 -07:00
Jiri Olsa d721def739 kallsyms: Make kallsyms_on_each_symbol generally available
Making kallsyms_on_each_symbol generally available, so it can be
used outside CONFIG_LIVEPATCH option in following changes.

Rather than adding another ifdef option let's make the function
generally available (when CONFIG_KALLSYMS option is defined).

Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-10 14:42:06 -07:00
Dmitrii Dolgov 9f88361273 bpf: Add bpf_link iterator
Implement bpf_link iterator to traverse links via bpf_seq_file
operations. The changeset is mostly shamelessly copied from
commit a228a64fc1 ("bpf: Add bpf_prog iterator")

Signed-off-by: Dmitrii Dolgov <9erthalion6@gmail.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220510155233.9815-2-9erthalion6@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-05-10 11:20:45 -07:00
Takshak Chahande 9263dddc7b bpf: Extend batch operations for map-in-map bpf-maps
This patch extends batch operations support for map-in-map map-types:
BPF_MAP_TYPE_HASH_OF_MAPS and BPF_MAP_TYPE_ARRAY_OF_MAPS

A usecase where outer HASH map holds hundred of VIP entries and its
associated reuse-ports per VIP stored in REUSEPORT_SOCKARRAY type
inner map, needs to do batch operation for performance gain.

This patch leverages the exiting generic functions for most of the batch
operations. As map-in-map's value contains the actual reference of the inner map,
for BPF_MAP_TYPE_HASH_OF_MAPS type, it needed an extra step to fetch the
map_id from the reference value.

selftests are added in next patch 2/2.

Signed-off-by: Takshak Chahande <ctakshak@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220510082221.2390540-1-ctakshak@fb.com
2022-05-10 10:34:57 -07:00
David Hildenbrand 40f2bbf711 mm/rmap: drop "compound" parameter from page_add_new_anon_rmap()
New anonymous pages are always mapped natively: only THP/khugepaged code
maps a new compound anonymous page and passes "true".  Otherwise, we're
just dealing with simple, non-compound pages.

Let's give the interface clearer semantics and document these.  Remove the
PageTransCompound() sanity check from page_add_new_anon_rmap().

Link: https://lkml.kernel.org/r/20220428083441.37290-9-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-09 18:20:43 -07:00
Yuntao Wang 43bf087848 bpf: Remove unused parameter from find_kfunc_desc_btf()
The func_id parameter in find_kfunc_desc_btf() is not used, get rid of it.

Fixes: 2357672c54 ("bpf: Introduce BPF support for kernel module function calls")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20220505070114.3522522-1-ytcoode@gmail.com
2022-05-09 17:45:21 -07:00
YueHaibing 494dcdf46e sched: Fix build warning without CONFIG_SYSCTL
IF CONFIG_SYSCTL is n, build warn:

kernel/sched/core.c:1782:12: warning: ‘sysctl_sched_uclamp_handler’ defined but not used [-Wunused-function]
 static int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~

sysctl_sched_uclamp_handler() is used while CONFIG_SYSCTL enabled,
wrap all related code with CONFIG_SYSCTL to fix this.

Fixes: 3267e0156c ("sched: Move uclamp_util sysctls to core.c")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-09 16:54:57 -07:00
YueHaibing 764aaf44cd reboot: Fix build warning without CONFIG_SYSCTL
If CONFIG_SYSCTL is n, build warn:

kernel/reboot.c:443:20: error: ‘kernel_reboot_sysctls_init’ defined but not used [-Werror=unused-function]
 static void __init kernel_reboot_sysctls_init(void)
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~

Move kernel_reboot_sysctls_init() to #ifdef block to fix this.

Fixes: 06d177662f ("kernel/reboot: move reboot sysctls to its own file")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-05-09 16:54:56 -07:00
Matthew Wilcox (Oracle) 7e0a126519 mm,fs: Remove aops->readpage
With all implementations of aops->readpage converted to aops->read_folio,
we can stop checking whether it's set and remove the member from aops.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2022-05-09 16:28:36 -04:00
Matthew Wilcox (Oracle) 5efe7448a1 fs: Introduce aops->read_folio
Change all the callers of ->readpage to call ->read_folio in preference,
if it exists.  This is a transitional duplication, and will be removed
by the end of the series.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2022-05-09 16:21:40 -04:00
Sven Schnelle 6d97af487d entry: Rename arch_check_user_regs() to arch_enter_from_user_mode()
arch_check_user_regs() is used at the moment to verify that struct pt_regs
contains valid values when entering the kernel from userspace. s390 needs
a place in the generic entry code to modify a cpu data structure when
switching from userspace to kernel mode. As arch_check_user_regs() is
exactly this, rename it to arch_enter_from_user_mode().

When entering the kernel from userspace, arch_check_user_regs() is
used to verify that struct pt_regs contains valid values. Note that
the NMI codepath doesn't call this function. s390 needs a place in the
generic entry code to modify a cpu data structure when switching from
userspace to kernel mode. As arch_check_user_regs() is exactly this,
rename it to arch_enter_from_user_mode().

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220504062351.2954280-2-tmricht@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-09 11:33:38 +02:00
Linus Torvalds ea82593bad A fix and an email address update:
- Mark the NMI safe time accessors notrace to prevent tracer recursion
     when they are selected as trace clocks.
 
   - John Stultz has a new email address
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Merge tag 'timers-urgent-2022-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fix from Thomas Gleixner:
 "A fix and an email address update:

   - Mark the NMI safe time accessors notrace to prevent tracer
     recursion when they are selected as trace clocks.

   - John Stultz has a new email address"

* tag 'timers-urgent-2022-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping: Mark NMI safe time accessors as notrace
  MAINTAINERS: Update email address for John Stultz
2022-05-08 11:18:11 -07:00
Linus Torvalds 9692df0581 A fix for the threaded interrupt core. A quick sequence of
request/free_irq() can result in a hang because the interrupt thread did
 not reach the thread function and got stopped in the kthread core
 already. That leaves a state active counter arround which makes a
 invocation of synchronized_irq() on that interrupt hang forever. Ensure
 that the thread reached the thread function in request_irq() to prevent
 that.
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Merge tag 'irq-urgent-2022-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fix from Thomas Gleixner:
 "A fix for the threaded interrupt core.

  A quick sequence of request/free_irq() can result in a hang because
  the interrupt thread did not reach the thread function and got stopped
  in the kthread core already. That leaves a state active counter
  arround which makes a invocation of synchronized_irq() on that
  interrupt hang forever.

  Ensure that the thread reached the thread function in request_irq() to
  prevent that"

* tag 'irq-urgent-2022-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq: Synchronize interrupt thread startup
2022-05-08 11:10:17 -07:00
Mark Rutland 8111e67dee stackleak: add on/off stack variants
The stackleak_erase() code dynamically handles being on a task stack or
another stack. In most cases, this is a fixed property of the caller,
which the caller is aware of, as an architecture might always return
using the task stack, or might always return using a trampoline stack.

This patch adds stackleak_erase_on_task_stack() and
stackleak_erase_off_task_stack() functions which callers can use to
avoid on_thread_stack() check and associated redundant work when the
calling stack is known. The existing stackleak_erase() is retained as a
safe default.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-13-mark.rutland@arm.com
2022-05-08 01:33:09 -07:00
Mark Rutland 77cf2b6dee stackleak: rework poison scanning
Currently we over-estimate the region of stack which must be erased.

To determine the region to be erased, we scan downwards for a contiguous
block of poison values (or the low bound of the stack). There are a few
minor problems with this today:

* When we find a block of poison values, we include this block within
  the region to erase.

  As this is included within the region to erase, this causes us to
  redundantly overwrite 'STACKLEAK_SEARCH_DEPTH' (128) bytes with
  poison.

* As the loop condition checks 'poison_count <= depth', it will run an
  additional iteration after finding the contiguous block of poison,
  decrementing 'erase_low' once more than necessary.

  As this is included within the region to erase, this causes us to
  redundantly overwrite an additional unsigned long with poison.

* As we always decrement 'erase_low' after checking an element on the
  stack, we always include the element below this within the region to
  erase.

  As this is included within the region to erase, this causes us to
  redundantly overwrite an additional unsigned long with poison.

  Note that this is not a functional problem. As the loop condition
  checks 'erase_low > task_stack_low', we'll never clobber the
  STACK_END_MAGIC. As we always decrement 'erase_low' after this, we'll
  never fail to erase the element immediately above the STACK_END_MAGIC.

In total, this can cause us to erase `128 + 2 * sizeof(unsigned long)`
bytes more than necessary, which is unfortunate.

This patch reworks the logic to find the address immediately above the
poisoned region, by finding the lowest non-poisoned address. This is
factored into a stackleak_find_top_of_poison() helper both for clarity
and so that this can be shared with the LKDTM test in subsequent
patches.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-8-mark.rutland@arm.com
2022-05-08 01:33:08 -07:00
Mark Rutland 0cfa2ccd28 stackleak: rework stack high bound handling
Prior to returning to userspace, we reset current->lowest_stack to a
reasonable high bound. Currently we do this by subtracting the arbitrary
value `THREAD_SIZE/64` from the top of the stack, for reasons lost to
history.

Looking at configurations today:

* On i386 where THREAD_SIZE is 8K, the bound will be 128 bytes. The
  pt_regs at the top of the stack is 68 bytes (with 0 to 16 bytes of
  padding above), and so this covers an additional portion of 44 to 60
  bytes.

* On x86_64 where THREAD_SIZE is at least 16K (up to 32K with KASAN) the
  bound will be at least 256 bytes (up to 512 with KASAN). The pt_regs
  at the top of the stack is 168 bytes, and so this cover an additional
  88 bytes of stack (up to 344 with KASAN).

* On arm64 where THREAD_SIZE is at least 16K (up to 64K with 64K pages
  and VMAP_STACK), the bound will be at least 256 bytes (up to 1024 with
  KASAN). The pt_regs at the top of the stack is 336 bytes, so this can
  fall within the pt_regs, or can cover an additional 688 bytes of
  stack.

Clearly the `THREAD_SIZE/64` value doesn't make much sense -- in the
worst case, this will cause more than 600 bytes of stack to be erased
for every syscall, even if actual stack usage were substantially
smaller.

This patches makes this slightly less nonsensical by consistently
resetting current->lowest_stack to the base of the task pt_regs. For
clarity and for consistency with the handling of the low bound, the
generation of the high bound is split into a helper with commentary
explaining why.

Since the pt_regs at the top of the stack will be clobbered upon the
next exception entry, we don't need to poison these at exception exit.
By using task_pt_regs() as the high stack boundary instead of
current_top_of_stack() we avoid some redundant poisoning, and the
compiler can share the address generation between the poisoning and
resetting of `current->lowest_stack`, making the generated code more
optimal.

It's not clear to me whether the existing `THREAD_SIZE/64` offset was a
dodgy heuristic to skip the pt_regs, or whether it was attempting to
minimize the number of times stackleak_check_stack() would have to
update `current->lowest_stack` when stack usage was shallow at the cost
of unconditionally poisoning a small portion of the stack for every exit
to userspace.

For now I've simply removed the offset, and if we need/want to minimize
updates for shallow stack usage it should be easy to add a better
heuristic atop, with appropriate commentary so we know what's going on.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-7-mark.rutland@arm.com
2022-05-08 01:33:08 -07:00
Mark Rutland 1723d39d2f stackleak: clarify variable names
The logic within __stackleak_erase() can be a little hard to follow, as
`boundary` switches from being the low bound to the high bound mid way
through the function, and `kstack_ptr` is used to represent the start of
the region to erase while `boundary` represents the end of the region to
erase.

Make this a little clearer by consistently using clearer variable names.
The `boundary` variable is removed, the bounds of the region to erase
are described by `erase_low` and `erase_high`, and bounds of the task
stack are described by `task_stack_low` and `task_stack_high`.

As the same time, remove the comment above the variables, since it is
unclear whether it's intended as rationale, a complaint, or a TODO, and
is more confusing than helpful.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-6-mark.rutland@arm.com
2022-05-08 01:33:08 -07:00
Mark Rutland 9ec79840d6 stackleak: rework stack low bound handling
In stackleak_task_init(), stackleak_track_stack(), and
__stackleak_erase(), we open-code skipping the STACK_END_MAGIC at the
bottom of the stack. Each case is implemented slightly differently, and
only the __stackleak_erase() case is commented.

In stackleak_task_init() and stackleak_track_stack() we unconditionally
add sizeof(unsigned long) to the lowest stack address. In
stackleak_task_init() we use end_of_stack() for this, and in
stackleak_track_stack() we use task_stack_page(). In __stackleak_erase()
we handle this by detecting if `kstack_ptr` has hit the stack end
boundary, and if so, conditionally moving it above the magic.

This patch adds a new stackleak_task_low_bound() helper which is used in
all three cases, which unconditionally adds sizeof(unsigned long) to the
lowest address on the task stack, with commentary as to why. This uses
end_of_stack() as stackleak_task_init() did prior to this patch, as this
is consistent with the code in kernel/fork.c which initializes the
STACK_END_MAGIC value.

In __stackleak_erase() we no longer need to check whether we've spilled
into the STACK_END_MAGIC value, as stackleak_track_stack() ensures that
`current->lowest_stack` stops immediately above this, and similarly the
poison scan will stop immediately above this.

For stackleak_task_init() and stackleak_track_stack() this results in no
change to code generation. For __stackleak_erase() the generated
assembly is slightly simpler and shorter.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-5-mark.rutland@arm.com
2022-05-08 01:33:08 -07:00
Mark Rutland ac7838b4e1 stackleak: remove redundant check
In __stackleak_erase() we check that the `erase_low` value derived from
`current->lowest_stack` is above the lowest legitimate stack pointer
value, but this is already enforced by stackleak_track_stack() when
recording the lowest stack value.

Remove the redundant check.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-4-mark.rutland@arm.com
2022-05-08 01:33:07 -07:00
Mark Rutland a12685e2d1 stackleak: move skip_erasing() check earlier
In stackleak_erase() we check skip_erasing() after accessing some fields
from current. As generating the address of current uses asm which
hazards with the static branch asm, this work is always performed, even
when the static branch is patched to jump to the return at the end of the
function.

This patch avoids this redundant work by moving the skip_erasing() check
earlier.

To avoid complicating initialization within stackleak_erase(), the body
of the function is split out into a __stackleak_erase() helper, with the
check left in a wrapper function. The __stackleak_erase() helper is
marked __always_inline to ensure that this is inlined into
stackleak_erase() and not instrumented.

Before this patch, on x86-64 w/ GCC 11.1.0 the start of the function is:

<stackleak_erase>:
   65 48 8b 04 25 00 00    mov    %gs:0x0,%rax
   00 00
   48 8b 48 20             mov    0x20(%rax),%rcx
   48 8b 80 98 0a 00 00    mov    0xa98(%rax),%rax
   66 90                   xchg   %ax,%ax  <------------ static branch
   48 89 c2                mov    %rax,%rdx
   48 29 ca                sub    %rcx,%rdx
   48 81 fa ff 3f 00 00    cmp    $0x3fff,%rdx

After this patch, on x86-64 w/ GCC 11.1.0 the start of the function is:

<stackleak_erase>:
   0f 1f 44 00 00          nopl   0x0(%rax,%rax,1)  <--- static branch
   65 48 8b 04 25 00 00    mov    %gs:0x0,%rax
   00 00
   48 8b 48 20             mov    0x20(%rax),%rcx
   48 8b 80 98 0a 00 00    mov    0xa98(%rax),%rax
   48 89 c2                mov    %rax,%rdx
   48 29 ca                sub    %rcx,%rdx
   48 81 fa ff 3f 00 00    cmp    $0x3fff,%rdx

Before this patch, on arm64 w/ GCC 11.1.0 the start of the function is:

<stackleak_erase>:
   d503245f        bti     c
   d5384100        mrs     x0, sp_el0
   f9401003        ldr     x3, [x0, #32]
   f9451000        ldr     x0, [x0, #2592]
   d503201f        nop  <------------------------------- static branch
   d503233f        paciasp
   cb030002        sub     x2, x0, x3
   d287ffe1        mov     x1, #0x3fff
   eb01005f        cmp     x2, x1

After this patch, on arm64 w/ GCC 11.1.0 the start of the function is:

<stackleak_erase>:
   d503245f        bti     c
   d503201f        nop  <------------------------------- static branch
   d503233f        paciasp
   d5384100        mrs     x0, sp_el0
   f9401003        ldr     x3, [x0, #32]
   d287ffe1        mov     x1, #0x3fff
   f9451000        ldr     x0, [x0, #2592]
   cb030002        sub     x2, x0, x3
   eb01005f        cmp     x2, x1

While this may not be a huge win on its own, moving the static branch
will permit further optimization of the body of the function in
subsequent patches.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-3-mark.rutland@arm.com
2022-05-08 01:33:07 -07:00
Kees Cook 595b893e20 randstruct: Reorganize Kconfigs and attribute macros
In preparation for Clang supporting randstruct, reorganize the Kconfigs,
move the attribute macros, and generalize the feature to be named
CONFIG_RANDSTRUCT for on/off, CONFIG_RANDSTRUCT_FULL for the full
randomization mode, and CONFIG_RANDSTRUCT_PERFORMANCE for the cache-line
sized mode.

Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-4-keescook@chromium.org
2022-05-08 01:33:06 -07:00
Zhen Lei 2e5920bb07 kdump: return -ENOENT if required cmdline option does not exist
According to the current crashkernel=Y,low support in other ARCHes, it's
an optional command-line option. When it doesn't exist, kernel will try
to allocate minimum required memory below 4G automatically.

However, __parse_crashkernel() returns '-EINVAL' for all error cases. It
can't distinguish the nonexistent option from invalid option.

Change __parse_crashkernel() to return '-ENOENT' for the nonexistent option
case. With this change, crashkernel,low memory will take the default
value if crashkernel=,low is not specified; while crashkernel reservation
will fail and bail out if an invalid option is specified.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Link: https://lore.kernel.org/r/20220506114402.365-2-thunder.leizhen@huawei.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-05-07 19:54:33 +01:00
Daniel Mentz 1e8ca62b79 kheaders: Have cpio unconditionally replace files
For out-of-tree builds, this script invokes cpio twice to copy header
files from the srctree and subsequently from the objtree. According to a
comment in the script, there might be situations in which certain files
already exist in the destination directory when header files are copied
from the objtree:

"The second CPIO can complain if files already exist which can happen
with out of tree builds having stale headers in srctree. Just silence
CPIO for now."

GNU cpio might simply print a warning like "newer or same age version
exists", but toybox cpio exits with a non-zero exit code unless the
command line option "-u" is specified.

To improve compatibility with toybox cpio, add the command line option
"-u" to unconditionally replace existing files in the destination
directory.

Signed-off-by: Daniel Mentz <danielmentz@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-05-08 03:16:59 +09:00
Eric W. Biederman 753550eb0c fork: Explicitly set PF_KTHREAD
Instead of implicitly inheriting PF_KTHREAD from the parent process
examine arguments in kernel_clone_args to see if PF_KTHREAD should be
set.  This makes knowledge of which new threads are kernel threads
explicit.

This also makes it so that init and the user mode helper processes
no longer have PF_KTHREAD set.

Link: https://lkml.kernel.org/r/20220506141512.516114-6-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-07 09:01:59 -05:00
Eric W. Biederman 5bd2e97c86 fork: Generalize PF_IO_WORKER handling
Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.

The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.

The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size".  These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().

Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-07 09:01:59 -05:00
Eric W. Biederman 36cb0e1cda fork: Explicity test for idle tasks in copy_thread
The architectures ia64 and parisc have special handling for the idle
thread in copy_process.  Add a flag named idle to kernel_clone_args
and use it to explicity test if an idle process is being created.

Fullfill the expectations of the rest of the copy_thread
implemetations and pass a function pointer in .stack from fork_idle().
This makes what is happening in copy_thread better defined, and is
useful to make idle threads less special.

Link: https://lkml.kernel.org/r/20220506141512.516114-3-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-07 09:01:59 -05:00
Eric W. Biederman c5febea095 fork: Pass struct kernel_clone_args into copy_thread
With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.

The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.

Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.

v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-07 09:01:48 -05:00
Eric W. Biederman 343f4c49f2 kthread: Don't allocate kthread_struct for init and umh
If kthread_is_per_cpu runs concurrently with free_kthread_struct the
kthread_struct that was just freed may be read from.

This bug was introduced by commit 40966e316f ("kthread: Ensure
struct kthread is present for all kthreads").  When kthread_struct
started to be allocated for all tasks that have PF_KTHREAD set.  This
in turn required the kthread_struct to be freed in kernel_execve and
violated the assumption that kthread_struct will have the same
lifetime as the task.

Looking a bit deeper this only applies to callers of kernel_execve
which is just the init process and the user mode helper processes.
These processes really don't want to be kernel threads but are for
historical reasons.  Mostly that copy_thread does not know how to take
a kernel mode function to the process with for processes without
PF_KTHREAD or PF_IO_WORKER set.

Solve this by not allocating kthread_struct for the init process and
the user mode helper processes.

This is done by adding a kthread member to struct kernel_clone_args.
Setting kthread in fork_idle and kernel_thread.  Adding
user_mode_thread that works like kernel_thread except it does not set
kthread.  In fork only allocating the kthread_struct if .kthread is set.

I have looked at kernel/kthread.c and since commit 40966e316f
("kthread: Ensure struct kthread is present for all kthreads") there
have been no assumptions added that to_kthread or __to_kthread will
not return NULL.

There are a few callers of to_kthread or __to_kthread that assume a
non-NULL struct kthread pointer will be returned.  These functions are
kthread_data(), kthread_parmme(), kthread_exit(), kthread(),
kthread_park(), kthread_unpark(), kthread_stop().  All of those functions
can reasonably expected to be called when it is know that a task is a
kthread so that assumption seems reasonable.

Cc: stable@vger.kernel.org
Fixes: 40966e316f ("kthread: Ensure struct kthread is present for all kthreads")
Reported-by: Максим Кутявин <maximkabox13@gmail.com>
Link: https://lkml.kernel.org/r/20220506141512.516114-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2022-05-06 14:49:44 -05:00
Marco Elver 701850dc0c printk, tracing: fix console tracepoint
The original intent of the 'console' tracepoint per the commit 9510035849
("printk/tracing: Add console output tracing") had been to "[...] record
any printk messages into the trace, regardless of the current console
loglevel. This can help correlate (existing) printk debugging with other
tracing."

Petr points out [1] that calling trace_console_rcuidle() in
call_console_driver() had been the wrong thing for a while, because
"printk() always used console_trylock() and the message was flushed to
the console only when the trylock succeeded. And it was always deferred
in NMI or when printed via printk_deferred()."

With the commit 09c5ba0aa2 ("printk: add kthread console printers"),
things only got worse, and calls to call_console_driver() no longer
happen with typical printk() calls but always appear deferred [2].

As such, the tracepoint can no longer serve its purpose to clearly
correlate printk() calls and other tracing, as well as breaks usecases
that expect every printk() call to result in a callback of the console
tracepoint. Notably, the KFENCE and KCSAN test suites, which want to
capture console output and assume a printk() immediately gives us a
callback to the console tracepoint.

Fix the console tracepoint by moving it into printk_sprint() [3].

One notable difference is that by moving tracing into printk_sprint(),
the 'text' will no longer include the "header" (loglevel and timestamp),
but only the raw message. Arguably this is less of a problem now that
the console tracepoint happens on the printk() call and isn't delayed.

Link: https://lore.kernel.org/all/Ym+WqKStCg%2FEHfh3@alley/ [1]
Link: https://lore.kernel.org/all/CA+G9fYu2kS0wR4WqMRsj2rePKV9XLgOU1PiXnMvpT+Z=c2ucHA@mail.gmail.com/ [2]
Link: https://lore.kernel.org/all/87fslup9dx.fsf@jogness.linutronix.de/ [3]
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Marco Elver <elver@google.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: John Ogness <john.ogness@linutronix.de>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220503073844.4148944-1-elver@google.com
2022-05-06 10:55:24 +02:00
Ingo Molnar d70522fc54 Linux 5.18-rc5
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Merge tag 'v5.18-rc5' into sched/core to pull in fixes & to resolve a conflict

 - sched/core is on a pretty old -rc1 base - refresh it to include recent fixes.
 - this also allows up to resolve a (trivial) .mailmap conflict

Conflicts:
	.mailmap

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2022-05-06 10:21:46 +02:00
Waiman Long 2685027fca cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp()
There are 3 places where the cpu and node masks of the top cpuset can
be initialized in the order they are executed:
 1) start_kernel -> cpuset_init()
 2) start_kernel -> cgroup_init() -> cpuset_bind()
 3) kernel_init_freeable() -> do_basic_setup() -> cpuset_init_smp()

The first cpuset_init() call just sets all the bits in the masks.
The second cpuset_bind() call sets cpus_allowed and mems_allowed to the
default v2 values. The third cpuset_init_smp() call sets them back to
v1 values.

For systems with cgroup v2 setup, cpuset_bind() is called once.  As a
result, cpu and memory node hot add may fail to update the cpu and node
masks of the top cpuset to include the newly added cpu or node in a
cgroup v2 environment.

For systems with cgroup v1 setup, cpuset_bind() is called again by
rebind_subsystem() when the v1 cpuset filesystem is mounted as shown
in the dmesg log below with an instrumented kernel.

  [    2.609781] cpuset_bind() called - v2 = 1
  [    3.079473] cpuset_init_smp() called
  [    7.103710] cpuset_bind() called - v2 = 0

smp_init() is called after the first two init functions.  So we don't
have a complete list of active cpus and memory nodes until later in
cpuset_init_smp() which is the right time to set up effective_cpus
and effective_mems.

To fix this cgroup v2 mask setup problem, the potentially incorrect
cpus_allowed & mems_allowed setting in cpuset_init_smp() are removed.
For cgroup v2 systems, the initial cpuset_bind() call will set the masks
correctly.  For cgroup v1 systems, the second call to cpuset_bind()
will do the right setup.

cc: stable@vger.kernel.org
Signed-off-by: Waiman Long <longman@redhat.com>
Tested-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2022-05-05 08:57:00 -10:00
Thomas Pfaff 8707898e22 genirq: Synchronize interrupt thread startup
A kernel hang can be observed when running setserial in a loop on a kernel
with force threaded interrupts. The sequence of events is:

   setserial
     open("/dev/ttyXXX")
       request_irq()
     do_stuff()
      -> serial interrupt
         -> wake(irq_thread)
	      desc->threads_active++;
     close()
       free_irq()
         kthread_stop(irq_thread)
     synchronize_irq() <- hangs because desc->threads_active != 0

The thread is created in request_irq() and woken up, but does not get on a
CPU to reach the actual thread function, which would handle the pending
wake-up. kthread_stop() sets the should stop condition which makes the
thread immediately exit, which in turn leaves the stale threads_active
count around.

This problem was introduced with commit 519cc8652b, which addressed a
interrupt sharing issue in the PCIe code.

Before that commit free_irq() invoked synchronize_irq(), which waits for
the hard interrupt handler and also for associated threads to complete.

To address the PCIe issue synchronize_irq() was replaced with
__synchronize_hardirq(), which only waits for the hard interrupt handler to
complete, but not for threaded handlers.

This was done under the assumption, that the interrupt thread already
reached the thread function and waits for a wake-up, which is guaranteed to
be handled before acting on the stop condition. The problematic case, that
the thread would not reach the thread function, was obviously overlooked.

Make sure that the interrupt thread is really started and reaches
thread_fn() before returning from __setup_irq().

This utilizes the existing wait queue in the interrupt descriptor. The
wait queue is unused for non-shared interrupts. For shared interrupts the
usage might cause a spurious wake-up of a waiter in synchronize_irq() or the
completion of a threaded handler might cause a spurious wake-up of the
waiter for the ready flag. Both are harmless and have no functional impact.

[ tglx: Amended changelog ]

Fixes: 519cc8652b ("genirq: Synchronize only with single thread on free_irq()")
Signed-off-by: Thomas Pfaff <tpfaff@pcs.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/552fe7b4-9224-b183-bb87-a8f36d335690@pcs.com
2022-05-05 11:54:05 +02:00
Marc Zyngier 4b88524c47 Merge remote-tracking branch 'arm64/for-next/sme' into kvmarm-master/next
Merge arm64's SME branch to resolve conflicts with the WFxT branch.

Signed-off-by: Marc Zyngier <maz@kernel.org>
2022-05-04 09:38:32 +01:00
Sargun Dhillon c2aa2dfef2 seccomp: Add wait_killable semantic to seccomp user notifier
This introduces a per-filter flag (SECCOMP_FILTER_FLAG_WAIT_KILLABLE_RECV)
that makes it so that when notifications are received by the supervisor the
notifying process will transition to wait killable semantics. Although wait
killable isn't a set of semantics formally exposed to userspace, the
concept is searchable. If the notifying process is signaled prior to the
notification being received by the userspace agent, it will be handled as
normal.

One quirk about how this is handled is that the notifying process
only switches to TASK_KILLABLE if it receives a wakeup from either
an addfd or a signal. This is to avoid an unnecessary wakeup of
the notifying task.

The reasons behind switching into wait_killable only after userspace
receives the notification are:
* Avoiding unncessary work - Often, workloads will perform work that they
  may abort (request racing comes to mind). This allows for syscalls to be
  aborted safely prior to the notification being received by the
  supervisor. In this, the supervisor doesn't end up doing work that the
  workload does not want to complete anyways.
* Avoiding side effects - We don't want the syscall to be interruptible
  once the supervisor starts doing work because it may not be trivial
  to reverse the operation. For example, unmounting a file system may
  take a long time, and it's hard to rollback, or treat that as
  reentrant.
* Avoid breaking runtimes - Various runtimes do not GC when they are
  during a syscall (or while running native code that subsequently
  calls a syscall). If many notifications are blocked, and not picked
  up by the supervisor, this can get the application into a bad state.

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503080958.20220-2-sargun@sargun.me
2022-05-03 14:11:58 -07:00
Paul E. McKenney be05ee5437 Merge branches 'docs.2022.04.20a', 'fixes.2022.04.20a', 'nocb.2022.04.11b', 'rcu-tasks.2022.04.11b', 'srcu.2022.05.03a', 'torture.2022.04.11b', 'torture-tasks.2022.04.20a' and 'torturescript.2022.04.20a' into HEAD
docs.2022.04.20a: Documentation updates.
fixes.2022.04.20a: Miscellaneous fixes.
nocb.2022.04.11b: Callback-offloading updates.
rcu-tasks.2022.04.11b: RCU-tasks updates.
srcu.2022.05.03a: Put SRCU on a memory diet.
torture.2022.04.11b: Torture-test updates.
torture-tasks.2022.04.20a: Avoid torture testing changing RCU configuration.
torturescript.2022.04.20a: Torture-test scripting updates.
2022-05-03 10:21:40 -07:00
Lukas Bulwahn 586e31d59c srcu: Drop needless initialization of sdp in srcu_gp_start()
Commit 9c7ef4c30f12 ("srcu: Make Tree SRCU able to operate without
snp_node array") initializes the local variable sdp differently depending
on the srcu's state in srcu_gp_start().  Either way, this initialization
overwrites the value used when sdp is defined.

This commit therefore drops this pointless definition-time initialization.
Although there is no functional change, compiler code generation may
be affected.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-05-03 10:20:57 -07:00
Paul E. McKenney 282d8998e9 srcu: Prevent expedited GPs and blocking readers from consuming CPU
If an SRCU reader blocks while a synchronize_srcu_expedited() waits for
that same reader, then that grace period will spawn an endless series of
workqueue handlers, consuming a full CPU.  This quickly gets pointless
because consuming more CPU isn't going to make that reader get done
faster, especially if it is blocked waiting for an external event.

This commit therefore spawns at most one pair of back-to-back workqueue
handlers per expedited grace period phase, instead inserting increasing
delays as that grace period phase grows older, but capped at 10 jiffies.
In any case, if there have been at least 100 back-to-back workqueue
handlers within a single jiffy, regardless of grace period or grace-period
phase, then a one-jiffy delay is inserted.

[ paulmck:  Apply feedback from kernel test robot. ]

Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Reported-by: Song Liu <song@kernel.org>
Tested-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-05-03 10:20:57 -07:00
Paul E. McKenney c2445d3878 srcu: Add contention check to call_srcu() srcu_data ->lock acquisition
This commit increases the sensitivity of contention detection by adding
checks to the acquisition of the srcu_data structure's lock on the
call_srcu() code path.

Co-developed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-05-03 10:20:57 -07:00
Paul E. McKenney a57ffb3c6b srcu: Automatically determine size-transition strategy at boot
This commit adds a srcutree.convert_to_big option of zero that causes
SRCU to decide at boot whether to wait for contention (small systems) or
immediately expand to large (large systems).  A new srcutree.big_cpu_lim
(defaulting to 128) defines how many CPUs constitute a large system.

Co-developed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2022-05-03 10:19:39 -07:00
Dave Airlie e954d2c94d Linux 5.18-rc5
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Backmerge tag 'v5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into drm-next

Linux 5.18-rc5

There was a build fix for arm I wanted in drm-next, so backmerge rather then cherry-pick.

Signed-off-by: Dave Airlie <airlied@redhat.com>
2022-05-03 16:08:48 +10:00
Christoph Hellwig f624506f98 kthread: unexport kthread_blkcg
kthread_blkcg is only used by the built-in blk-cgroup code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-05-02 14:06:20 -06:00
Christoph Hellwig bbb1ebe7a9 blk-cgroup: replace bio_blkcg with bio_blkcg_css
All callers of bio_blkcg actually want the CSS, so replace it with an
interface that does return the CSS.  This now allows to move
struct blkcg_gq to block/blk-cgroup.h instead of exposing it in a
public header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-05-02 14:06:20 -06:00
Christoph Hellwig f4a6a61cb6 blktrace: cleanup the __trace_note_message interface
Pass the cgroup_subsys_state instead of a the blkg so that blktrace
doesn't need to poke into blk-cgroup internals, and give the name a
blk prefix as the current name is way too generic for a public
interface.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220420042723.1010598-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-05-02 14:06:20 -06:00
Maciej W. Rozycki f4b62e1e11 time/sched_clock: Fix formatting of frequency reporting code
Use flat rather than nested indentation for chained else/if clauses as 
per coding-style.rst:

	if (x == y) {
		..
	} else if (x > y) {
		...
	} else {
		....
	}

This also improves readability.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204240148220.9383@angie.orcam.me.uk
2022-05-02 14:29:04 +02:00
Maciej W. Rozycki cc1b923a4e time/sched_clock: Use Hz as the unit for clock rate reporting below 4kHz
The kernel uses kHz as the unit for clock rates reported between 1MHz
(inclusive) and 4MHz (exclusive), e.g.:

 sched_clock: 64 bits at 1000kHz, resolution 1000ns, wraps every 2199023255500ns

This reduces the amount of data lost due to rounding, but hasn't been
replicated for the kHz range when support was added for proper reporting of
sub-kHz clock rates.  Take the same approach for rates between 1kHz
(inclusive) and 4kHz (exclusive), which makes it consistent.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204240106380.9383@angie.orcam.me.uk
2022-05-02 14:29:04 +02:00
Maciej W. Rozycki 92067440f1 time/sched_clock: Round the frequency reported to nearest rather than down
The frequency reported for clock sources are rounded down, which gives
misleading figures, e.g.:

 I/O ASIC clock frequency 24999480Hz
 sched_clock: 32 bits at 24MHz, resolution 40ns, wraps every 85901132779ns
 MIPS counter frequency 59998512Hz
 sched_clock: 32 bits at 59MHz, resolution 16ns, wraps every 35792281591ns

Rounding to nearest is more adequate:

 I/O ASIC clock frequency 24999664Hz
 sched_clock: 32 bits at 25MHz, resolution 40ns, wraps every 85900499947ns
 MIPS counter frequency 59999728Hz
 sched_clock: 32 bits at 60MHz, resolution 16ns, wraps every 35791556599ns

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204240055590.9383@angie.orcam.me.uk
2022-05-02 14:29:04 +02:00
Minghao Chi ce4818957f genirq: Use pm_runtime_resume_and_get() instead of pm_runtime_get_sync()
pm_runtime_resume_and_get() achieves the same and simplifies the code.

[ tglx: Simplify it further by presetting retval ]

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi <chi.minghao@zte.com.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220418110716.2559453-1-chi.minghao@zte.com.cn
2022-05-02 14:08:08 +02:00
Thomas Gleixner 90be8d6c1f timekeeping: Consolidate fast timekeeper
Provide a inline function which replaces the copy & pasta.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220415091921.072296632@linutronix.de
2022-05-02 14:00:20 +02:00
Thomas Gleixner eff4849f92 timekeeping: Annotate ktime_get_boot_fast_ns() with data_race()
Accessing timekeeper::offset_boot in ktime_get_boot_fast_ns() is an
intended data race as the reader side cannot synchronize with a writer and
there is no space in struct tk_read_base of the NMI safe timekeeper.

Mark it so.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220415091920.956045162@linutronix.de
2022-05-02 14:00:20 +02:00
Fenghua Yu 2667ed10d9 mm: Fix PASID use-after-free issue
The PASID is being freed too early.  It needs to stay around until after
device drivers that might be using it have had a chance to clear it out
of the hardware.

The relevant refcounts are:

  mmget() /mmput()  refcount the mm's address space
  mmgrab()/mmdrop() refcount the mm itself

The PASID is currently tied to the life of the mm's address space and freed
in __mmput().  This makes logical sense because the PASID can't be used
once the address space is gone.

But, this misses an important point: even after the address space is gone,
the PASID will still be programmed into a device.  Device drivers might,
for instance, still need to flush operations that are outstanding and need
to use that PASID.  They do this at file->release() time.

Device drivers call the IOMMU driver to hold a reference on the mm itself
and drop it at file->release() time.  But, the IOMMU driver holds a
reference on the mm itself, not the address space.  The address space (and
the PASID) is long gone by the time the driver tries to clean up.  This is
effectively a use-after-free bug on the PASID.

To fix this, move the PASID free operation from __mmput() to __mmdrop().
This ensures that the IOMMU driver's existing mmgrab() keeps the PASID
allocated until it drops its mm reference.

Fixes: 701fac4038 ("iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit")
Reported-by: Zhangfei Gao <zhangfei.gao@foxmail.com>
Suggested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Zhangfei Gao <zhangfei.gao@foxmail.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20220428180041.806809-1-fenghua.yu@intel.com
2022-05-01 10:17:17 +02:00
Sebastian Andrzej Siewior 1a90bfd220 smp: Make softirq handling RT safe in flush_smp_call_function_queue()
flush_smp_call_function_queue() invokes do_softirq() which is not available
on PREEMPT_RT. flush_smp_call_function_queue() is invoked from the idle
task and the migration task with preemption or interrupts disabled.

So RT kernels cannot process soft interrupts in that context as that has to
acquire 'sleeping spinlocks' which is not possible with preemption or
interrupts disabled and forbidden from the idle task anyway.

The currently known SMP function call which raises a soft interrupt is in
the block layer, but this functionality is not enabled on RT kernels due to
latency and performance reasons.

RT could wake up ksoftirqd unconditionally, but this wants to be avoided if
there were soft interrupts pending already when this is invoked in the
context of the migration task. The migration task might have preempted a
threaded interrupt handler which raised a soft interrupt, but did not reach
the local_bh_enable() to process it. The "running" ksoftirqd might prevent
the handling in the interrupt thread context which is causing latency
issues.

Add a new function which handles this case explicitely for RT and falls
back to do_softirq() on !RT kernels. In the RT case this warns when one of
the flushed SMP function calls raised a soft interrupt so this can be
investigated.

[ tglx: Moved the RT part out of SMP code ]

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/YgKgL6aPj8aBES6G@linutronix.de
Link: https://lore.kernel.org/r/20220413133024.356509586@linutronix.de
2022-05-01 10:03:43 +02:00
Thomas Gleixner 16bf5a5e1e smp: Rename flush_smp_call_function_from_idle()
This is invoked from the stopper thread too, which is definitely not idle.
Rename it to flush_smp_call_function_queue() and fixup the callers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220413133024.305001096@linutronix.de
2022-05-01 10:03:43 +02:00
Thomas Gleixner d664e39912 sched: Fix missing prototype warnings
A W=1 build emits more than a dozen missing prototype warnings related to
scheduler and scheduler specific includes.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220413133024.249118058@linutronix.de
2022-05-01 10:03:43 +02:00
Jens Axboe e788be95a5 task_work: allow TWA_SIGNAL without a rescheduling IPI
Some use cases don't always need an IPI when sending a TWA_SIGNAL
notification. Add TWA_SIGNAL_NO_IPI, which is just like TWA_SIGNAL, except
it doesn't send an IPI to the target task. It merely sets
TIF_NOTIFY_SIGNAL and wakes up the task.

This can be useful in avoiding a forceful transition to the kernel if the
task is running in userspace. Depending on the task_work in question, it
may be quite fine waiting for the next reschedule or kernel enter anyway,
or the use case may even have other mechanisms for hinting to the task
that a transition may be useful. This can drive more cooperative
scheduling of task_work.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/821f42b6-7d91-8074-8212-d34998097de4@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-04-30 08:39:32 -06:00
xu xin edc73c7261 kernel: make taskstats available from all net namespaces
If getdelays runs in a non-init network namespace, it will fail in getting
delayacct stats even if it has privilege of root user, which seems to be
not very reasonable.  We can simply reproduce this by executing commands:

	unshare -n
	getdelays -d -p <pid>

I don't think net namespace should be an obstacle to the normal execution
of getdelay function.  So let's make it available from all net namespaces.

Link: https://lkml.kernel.org/r/20220412071946.2532318-1-xu.xin16@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: "Dr. Thomas Orgis" <thomas.orgis@uni-hamburg.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ismael Luceno <ismael@iodev.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-04-29 14:38:03 -07:00
Dr. Thomas Orgis 0e0af57e0e taskstats: version 12 with thread group and exe info
The task exit struct needs some crucial information to be able to provide
an enhanced version of process and thread accounting.  This change
provides:

1. ac_tgid in additon to ac_pid
2. thread group execution walltime in ac_tgetime
3. flag AGROUP in ac_flag to indicate the last task
   in a thread group / process
4. device ID and inode of task's /proc/self/exe in
   ac_exe_dev and ac_exe_inode
5. tools/accounting/procacct as demonstrator

When a task exits, taskstats are reported to userspace including the
task's pid and ppid, but without the id of the thread group this task is
part of.  Without the tgid, the stats of single tasks cannot be correlated
to each other as a thread group (process).

The taskstats documentation suggests that on process exit a data set
consisting of accumulated stats for the whole group is produced.  But such
an additional set of stats is only produced for actually multithreaded
processes, not groups that had only one thread, and also those stats only
contain data about delay accounting and not the more basic information
about CPU and memory resource usage.  Adding the AGROUP flag to be set
when the last task of a group exited enables determination of process end
also for single-threaded processes.

My applicaton basically does enhanced process accounting with summed
cputime, biggest maxrss, tasks per process.  The data is not available
with the traditional BSD process accounting (which is not designed to be
extensible) and the taskstats interface allows more efficient on-the-fly
grouping and summing of the stats, anyway, without intermediate disk
writes.

Furthermore, I do carry statistics on which exact program binary is used
how often with associated resources, getting a picture on how important
which parts of a collection of installed scientific software in different
versions are, and how well they put load on the machine.  This is enabled
by providing information on /proc/self/exe for each task.  I assume the
two 64-bit fields for device ID and inode are more appropriate than the
possibly large resolved path to keep the data volume down.

Add the tgid to the stats to complete task identification, the flag AGROUP
to mark the last task of a group, the group wallclock time, and
inode-based identification of the associated executable file.

Add tools/accounting/procacct.c as a simplified fork of getdelays.c to
demonstrate process and thread accounting.

[thomas.orgis@uni-hamburg.de: fix version number in comment]
  Link: https://lkml.kernel.org/r/20220405003601.7a5f6008@plasteblaster
Link: https://lkml.kernel.org/r/20220331004106.64e5616b@plasteblaster
Signed-off-by: Dr. Thomas Orgis <thomas.orgis@uni-hamburg.de>
Reviewed-by: Ismael Luceno <ismael@iodev.co.uk>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-04-29 14:38:03 -07:00
Michal Orzel 16b0b7adab kexec: remove redundant assignments
Get rid of redundant assignments which end up in values not being read
either because they are overwritten or the function ends.

Reported by clang-tidy [deadcode.DeadStores]

Link: https://lkml.kernel.org/r/20220326180948.192154-1-michalorzel.eng@gmail.com
Signed-off-by: Michal Orzel <michalorzel.eng@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Michal Orzel <michalorzel.eng@gmail.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-04-29 14:38:03 -07:00
Tiezhu Yang f26b2afd53 ptrace: remove redudant check of #ifdef PTRACE_SINGLESTEP
Patch series "ptrace: do some cleanup".


This patch (of 3):

PTRACE_SINGLESTEP is always defined as 9 in include/uapi/linux/ptrace.h,
remove redudant check of #ifdef PTRACE_SINGLESTEP.

Link: https://lkml.kernel.org/r/1649240981-11024-2-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-04-29 14:38:02 -07:00
Rasmus Villemoes 67fca000e1 lib/Kconfig.debug: remove more CONFIG_..._VALUE indirections
As in "kernel/panic.c: remove CONFIG_PANIC_ON_OOPS_VALUE indirection",
use the IS_ENABLED() helper rather than having a hidden config option.

Link: https://lkml.kernel.org/r/20220321121301.1389693-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-04-29 14:38:00 -07:00
Haowen Bai c06d7aaf29 kernel: pid_namespace: use NULL instead of using plain integer as pointer
This fixes the following sparse warnings:
kernel/pid_namespace.c:55:77: warning: Using plain integer as NULL pointer

Link: https://lkml.kernel.org/r/1647944288-2806-1-git-send-email-baihaowen@meizu.com
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-04-29 14:38:00 -07:00
Sargun Dhillon 4cbf6f6211 seccomp: Use FIFO semantics to order notifications
Previously, the seccomp notifier used LIFO semantics, where each
notification would be added on top of the stack, and notifications
were popped off the top of the stack. This could result one process
that generates a large number of notifications preventing other
notifications from being handled. This patch moves from LIFO (stack)
semantics to FIFO (queue semantics).

Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220428015447.13661-1-sargun@sargun.me
2022-04-29 11:30:54 -07:00
Chengming Zhou e999995c84 ftrace: cleanup ftrace_graph_caller enable and disable
The ftrace_[enable,disable]_ftrace_graph_caller() are used to do
special hooks for graph tracer, which are not needed on some ARCHs
that use graph_ops:func function to install return_hooker.

So introduce the weak version in ftrace core code to cleanup
in x86.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20220420160006.17880-1-zhouchengming@bytedance.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-04-29 19:21:12 +01:00
Dietmar Eggemann 97956dd278 sched/fair: Remove cfs_rq_tg_path()
cfs_rq_tg_path() is used by a tracepoint-to traceevent (tp-2-te)
converter to format the path of a taskgroup or autogroup respectively.
It doesn't have any in-kernel users after the removal of the
sched_trace_cfs_rq_path() helper function.

cfs_rq_tg_path() can be coded in a tp-2-te converter.

Remove it from kernel/sched/fair.c.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220428144338.479094-3-qais.yousef@arm.com
2022-04-29 11:06:29 +02:00
Dietmar Eggemann 50e7b416d2 sched/fair: Remove sched_trace_*() helper functions
We no longer need them as we can use DWARF debug info or BTF + pahole to
re-generate the required structs to compile against them for a given
kernel.

This moves the burden of maintaining these helper functions to the
module.

	https://github.com/qais-yousef/sched_tp

Note that pahole v1.15 is required at least for using DWARF. And for BTF
v1.23 which is not yet released will be required. There's alignment
problem that will lead to crashes in earlier versions when used with
BTF.

We should have enough infrastructure to make these helper functions now
obsolete, so remove them.

[Rewrote commit message to reflect the new alternative]
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220428144338.479094-2-qais.yousef@arm.com
2022-04-29 11:06:29 +02:00
Dietmar Eggemann 4e3c7d338a sched/fair: Refactor cpu_util_without()
Except the 'task has no contribution or is new' condition at the
beginning of cpu_util_without(), which it shares with the load and
runnable counterpart functions, a cpu_util_next(..., dst_cpu = -1)
call can replace the rest of it.

The UTIL_EST specific check that task util_est has to be subtracted
from the CPU one in case of an enqueued (or current (to cater for the
wakeup - lb race)) task has to be moved to cpu_util_next().
This was initially introduced by commit c469933e77
("sched/fair: Fix cpu_util_wake() for 'execl' type workloads").
UnixBench's `execl` throughput tests were run on the dual socket 40
CPUs Intel E5-2690 v2 to make sure it doesn't regress again.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20220318163656.954440-1-dietmar.eggemann@arm.com
2022-04-29 11:06:29 +02:00
Kurt Kanzenbach 2c33d775ef timekeeping: Mark NMI safe time accessors as notrace
Mark the CLOCK_MONOTONIC fast time accessors as notrace. These functions are
used in tracing to retrieve timestamps, so they should not recurse.

Fixes: 4498e7467e ("time: Parametrize all tk_fast_mono users")
Fixes: f09cb9a180 ("time: Introduce tk_fast_raw")
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220426175338.3807ca4f@gandalf.local.home/
Link: https://lore.kernel.org/r/20220428062432.61063-1-kurt@linutronix.de
2022-04-29 00:07:53 +02:00
Jakub Kicinski 0e55546b18 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
include/linux/netdevice.h
net/core/dev.c
  6510ea973d ("net: Use this_cpu_inc() to increment net->core_stats")
  794c24e992 ("net-core: rx_otherhost_dropped to core_stats")
https://lore.kernel.org/all/20220428111903.5f4304e0@canb.auug.org.au/

drivers/net/wan/cosa.c
  d48fea8401 ("net: cosa: fix error check return value of register_chrdev()")
  89fbca3307 ("net: wan: remove support for COSA and SRP synchronous serial boards")
https://lore.kernel.org/all/20220428112130.1f689e5e@canb.auug.org.au/

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-28 13:02:01 -07:00
Linus Torvalds 249aca0d3d Networking fixes for 5.18-rc5, including fixes from bluetooth, bpf
and netfilter.
 
 Current release - new code bugs:
 
  - bridge: switchdev: check br_vlan_group() return value
 
  - use this_cpu_inc() to increment net->core_stats, fix preempt-rt
 
 Previous releases - regressions:
 
  - eth: stmmac: fix write to sgmii_adapter_base
 
 Previous releases - always broken:
 
  - netfilter: nf_conntrack_tcp: re-init for syn packets only,
    resolving issues with TCP fastopen
 
  - tcp: md5: fix incorrect tcp_header_len for incoming connections
 
  - tcp: fix F-RTO may not work correctly when receiving DSACK
 
  - tcp: ensure use of most recently sent skb when filling rate samples
 
  - tcp: fix potential xmit stalls caused by TCP_NOTSENT_LOWAT
 
  - virtio_net: fix wrong buf address calculation when using xdp
 
  - xsk: fix forwarding when combining copy mode with busy poll
 
  - xsk: fix possible crash when multiple sockets are created
 
  - bpf: lwt: fix crash when using bpf_skb_set_tunnel_key() from
    bpf_xmit lwt hook
 
  - sctp: null-check asoc strreset_chunk in sctp_generate_reconf_event
 
  - wireguard: device: check for metadata_dst with skb_valid_dst()
 
  - netfilter: update ip6_route_me_harder to consider L3 domain
 
  - gre: make o_seqno start from 0 in native mode
 
  - gre: switch o_seqno to atomic to prevent races in collect_md mode
 
 Misc:
 
  - add Eric Dumazet to networking maintainers
 
  - dt: dsa: realtek: remove realtek,rtl8367s string
 
  - netfilter: flowtable: Remove the empty file
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Including fixes from bluetooth, bpf and netfilter.

  Current release - new code bugs:

   - bridge: switchdev: check br_vlan_group() return value

   - use this_cpu_inc() to increment net->core_stats, fix preempt-rt

  Previous releases - regressions:

   - eth: stmmac: fix write to sgmii_adapter_base

  Previous releases - always broken:

   - netfilter: nf_conntrack_tcp: re-init for syn packets only,
     resolving issues with TCP fastopen

   - tcp: md5: fix incorrect tcp_header_len for incoming connections

   - tcp: fix F-RTO may not work correctly when receiving DSACK

   - tcp: ensure use of most recently sent skb when filling rate samples

   - tcp: fix potential xmit stalls caused by TCP_NOTSENT_LOWAT

   - virtio_net: fix wrong buf address calculation when using xdp

   - xsk: fix forwarding when combining copy mode with busy poll

   - xsk: fix possible crash when multiple sockets are created

   - bpf: lwt: fix crash when using bpf_skb_set_tunnel_key() from
     bpf_xmit lwt hook

   - sctp: null-check asoc strreset_chunk in sctp_generate_reconf_event

   - wireguard: device: check for metadata_dst with skb_valid_dst()

   - netfilter: update ip6_route_me_harder to consider L3 domain

   - gre: make o_seqno start from 0 in native mode

   - gre: switch o_seqno to atomic to prevent races in collect_md mode

  Misc:

   - add Eric Dumazet to networking maintainers

   - dt: dsa: realtek: remove realtek,rtl8367s string

   - netfilter: flowtable: Remove the empty file"

* tag 'net-5.18-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (65 commits)
  tcp: fix F-RTO may not work correctly when receiving DSACK
  Revert "ibmvnic: Add ethtool private flag for driver-defined queue limits"
  net: enetc: allow tc-etf offload even with NETIF_F_CSUM_MASK
  ixgbe: ensure IPsec VF<->PF compatibility
  MAINTAINERS: Update BNXT entry with firmware files
  netfilter: nft_socket: only do sk lookups when indev is available
  net: fec: add missing of_node_put() in fec_enet_init_stop_mode()
  bnx2x: fix napi API usage sequence
  tls: Skip tls_append_frag on zero copy size
  Add Eric Dumazet to networking maintainers
  netfilter: conntrack: fix udp offload timeout sysctl
  netfilter: nf_conntrack_tcp: re-init for syn packets only
  net: dsa: lantiq_gswip: Don't set GSWIP_MII_CFG_RMII_CLK
  net: Use this_cpu_inc() to increment net->core_stats
  Bluetooth: hci_sync: Cleanup hci_conn if it cannot be aborted
  Bluetooth: hci_event: Fix creating hci_conn object on error status
  Bluetooth: hci_event: Fix checking for invalid handle on error status
  ice: fix use-after-free when deinitializing mailbox snapshot
  ice: wait 5 s for EMP reset after firmware flash
  ice: Protect vf_state check by cfg_lock in ice_vc_process_vf_msg()
  ...
2022-04-28 12:34:50 -07:00
Jakub Kicinski 50c6afabfd Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2022-04-27

We've added 85 non-merge commits during the last 18 day(s) which contain
a total of 163 files changed, 4499 insertions(+), 1521 deletions(-).

The main changes are:

1) Teach libbpf to enhance BPF verifier log with human-readable and relevant
   information about failed CO-RE relocations, from Andrii Nakryiko.

2) Add typed pointer support in BPF maps and enable it for unreferenced pointers
   (via probe read) and referenced ones that can be passed to in-kernel helpers,
   from Kumar Kartikeya Dwivedi.

3) Improve xsk to break NAPI loop when rx queue gets full to allow for forward
   progress to consume descriptors, from Maciej Fijalkowski & Björn Töpel.

4) Fix a small RCU read-side race in BPF_PROG_RUN routines which dereferenced
   the effective prog array before the rcu_read_lock, from Stanislav Fomichev.

5) Implement BPF atomic operations for RV64 JIT, and add libbpf parsing logic
   for USDT arguments under riscv{32,64}, from Pu Lehui.

6) Implement libbpf parsing of USDT arguments under aarch64, from Alan Maguire.

7) Enable bpftool build for musl and remove nftw with FTW_ACTIONRETVAL usage
   so it can be shipped under Alpine which is musl-based, from Dominique Martinet.

8) Clean up {sk,task,inode} local storage trace RCU handling as they do not
   need to use call_rcu_tasks_trace() barrier, from KP Singh.

9) Improve libbpf API documentation and fix error return handling of various
   API functions, from Grant Seltzer.

10) Enlarge offset check for bpf_skb_{load,store}_bytes() helpers given data
    length of frags + frag_list may surpass old offset limit, from Liu Jian.

11) Various improvements to prog_tests in area of logging, test execution
    and by-name subtest selection, from Mykola Lysenko.

12) Simplify map_btf_id generation for all map types by moving this process
    to build time with help of resolve_btfids infra, from Menglong Dong.

13) Fix a libbpf bug in probing when falling back to legacy bpf_probe_read*()
    helpers; the probing caused always to use old helpers, from Runqing Yang.

14) Add support for ARCompact and ARCv2 platforms for libbpf's PT_REGS
    tracing macros, from Vladimir Isaev.

15) Cleanup BPF selftests to remove old & unneeded rlimit code given kernel
    switched to memcg-based memory accouting a while ago, from Yafang Shao.

16) Refactor of BPF sysctl handlers to move them to BPF core, from Yan Zhu.

17) Fix BPF selftests in two occasions to work around regressions caused by latest
    LLVM to unblock CI until their fixes are worked out, from Yonghong Song.

18) Misc cleanups all over the place, from various others.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (85 commits)
  selftests/bpf: Add libbpf's log fixup logic selftests
  libbpf: Fix up verifier log for unguarded failed CO-RE relos
  libbpf: Simplify bpf_core_parse_spec() signature
  libbpf: Refactor CO-RE relo human description formatting routine
  libbpf: Record subprog-resolved CO-RE relocations unconditionally
  selftests/bpf: Add CO-RE relos and SEC("?...") to linked_funcs selftests
  libbpf: Avoid joining .BTF.ext data with BPF programs by section name
  libbpf: Fix logic for finding matching program for CO-RE relocation
  libbpf: Drop unhelpful "program too large" guess
  libbpf: Fix anonymous type check in CO-RE logic
  bpf: Compute map_btf_id during build time
  selftests/bpf: Add test for strict BTF type check
  selftests/bpf: Add verifier tests for kptr
  selftests/bpf: Add C tests for kptr
  libbpf: Add kptr type tag macros to bpf_helpers.h
  bpf: Make BTF type match stricter for release arguments
  bpf: Teach verifier about kptr_get kfunc helpers
  bpf: Wire up freeing of referenced kptr
  bpf: Populate pairs of btf_id and destructor kfunc in btf
  bpf: Adapt copy_map_value for multiple offset case
  ...
====================

Link: https://lore.kernel.org/r/20220427224758.20976-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-27 17:09:32 -07:00
Jakub Kicinski 347cb5deae Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:

====================
pull-request: bpf 2022-04-27

We've added 5 non-merge commits during the last 20 day(s) which contain
a total of 6 files changed, 34 insertions(+), 12 deletions(-).

The main changes are:

1) Fix xsk sockets when rx and tx are separately bound to the same umem, also
   fix xsk copy mode combined with busy poll, from Maciej Fijalkowski.

2) Fix BPF tunnel/collect_md helpers with bpf_xmit lwt hook usage which triggered
   a crash due to invalid metadata_dst access, from Eyal Birger.

3) Fix release of page pool in XDP live packet mode, from Toke Høiland-Jørgensen.

4) Fix potential NULL pointer dereference in kretprobes, from Adam Zabrocki.

   (Masami & Steven preferred this small fix to be routed via bpf tree given it's
    follow-up fix to Masami's rethook work that went via bpf earlier, too.)

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  xsk: Fix possible crash when multiple sockets are created
  kprobes: Fix KRETPROBES when CONFIG_KRETPROBE_ON_RETHOOK is set
  bpf, lwt: Fix crash when using bpf_skb_set_tunnel_key() from bpf_xmit lwt hook
  bpf: Fix release of page_pool in BPF_PROG_RUN in test runner
  xsk: Fix l2fwd for copy mode + busy poll combo
====================

Link: https://lore.kernel.org/r/20220427212748.9576-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-27 15:18:40 -07:00
Jakob Koschel ba27d85558 tracing: Remove check of list iterator against head past the loop body
When list_for_each_entry() completes the iteration over the whole list
without breaking the loop, the iterator value will be a bogus pointer
computed based on the head element.

While it is safe to use the pointer to determine if it was computed
based on the head element, either with list_entry_is_head() or
&pos->member == head, using the iterator variable after the loop should
be avoided.

In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to point to the found element [1].

Link: https://lkml.kernel.org/r/20220427170734.819891-5-jakobkoschel@gmail.com

Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 17:19:31 -04:00
Jakob Koschel 45e333ce2a tracing: Replace usage of found with dedicated list iterator variable
To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.

Link: https://lkml.kernel.org/r/20220427170734.819891-4-jakobkoschel@gmail.com

Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 17:19:31 -04:00
Jakob Koschel 99d8ae4ec8 tracing: Remove usage of list iterator variable after the loop
In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to point to the found element
[1].

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Link: https://lkml.kernel.org/r/20220427170734.819891-3-jakobkoschel@gmail.com

Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 17:19:30 -04:00
Jakob Koschel 1da27a2505 tracing: Remove usage of list iterator after the loop body
In preparation to limit the scope of the list iterator variable to the
traversal loop, use a dedicated pointer to point to the found element
[1].

Before, the code implicitly used the head when no element was found
when using &pos->list. Since the new variable is only set if an
element was found, the head needs to be used explicitly if the
variable is NULL.

Link: https://lkml.kernel.org/r/20220427170734.819891-2-jakobkoschel@gmail.com

Cc: Ingo Molnar <mingo@redhat.com>
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 17:19:30 -04:00
Kurt Kanzenbach c575afe21c tracing: Introduce trace clock tai
A fast/NMI safe accessor for CLOCK_TAI has been introduced.
Use it for adding the additional trace clock "tai".

Link: https://lkml.kernel.org/r/20220414091805.89667-3-kurt@linutronix.de

Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 17:19:30 -04:00
Steven Rostedt (Google) f03f2abce4 ring-buffer: Have 32 bit time stamps use all 64 bits
When the new logic was made to handle deltas of events from interrupts
that interrupted other events, it required 64 bit local atomics.
Unfortunately, 64 bit local atomics are expensive on 32 bit architectures.
Thus, commit 10464b4aa6 ("ring-buffer: Add rb_time_t 64 bit operations
for speeding up 32 bit") created a type of seq lock timer for 32 bits.
It used two 32 bit local atomics, but required 2 bits from them each for
synchronization, making it only 60 bits.

Add a new "msb" field to hold the extra 4 bits that are cut off.

Link: https://lore.kernel.org/all/20220426175338.3807ca4f@gandalf.local.home/
Link: https://lkml.kernel.org/r/20220427170812.53cc7139@gandalf.local.home

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 17:19:30 -04:00
Steven Rostedt (Google) 6695da58f9 ring-buffer: Have absolute time stamps handle large numbers
There's an absolute timestamp event in the ring buffer, but this only
saves 59 bits of the timestamp, as the 5 MSB is used for meta data
(stating it is an absolute time stamp). This was never an issue as all the
clocks currently in use never used those 5 MSB. But now there's a new
clock (TAI) that does.

To handle this case, when reading an absolute timestamp, a previous full
timestamp is passed in, and the 5 MSB of that timestamp is OR'd to the
absolute timestamp (if any of the 5 MSB are set), and then to test for
overflow, if the new result is smaller than the passed in previous
timestamp, then 1 << 59 is added to it.

All the extra processing is done on the reader "slow" path, with the
exception of the "too big delta" check, and the reading of timestamps
for histograms.

Note, libtraceevent will need to be updated to handle this case as well.
But this is not a user space regression, as user space was never able to
handle any timestamps that used more than 59 bits.

Link: https://lore.kernel.org/all/20220426175338.3807ca4f@gandalf.local.home/
Link: https://lkml.kernel.org/r/20220427153339.16c33f75@gandalf.local.home

Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-27 15:59:44 -04:00
Tony Luck b041b525da x86/split_lock: Make life miserable for split lockers
In https://lore.kernel.org/all/87y22uujkm.ffs@tglx/ Thomas
said:

  Its's simply wishful thinking that stuff gets fixed because of a
  WARN_ONCE(). This has never worked. The only thing which works is to
  make stuff fail hard or slow it down in a way which makes it annoying
  enough to users to complain.

He was talking about WBINVD. But it made me think about how we use the
split lock detection feature in Linux.

Existing code has three options for applications:

 1) Don't enable split lock detection (allow arbitrary split locks)
 2) Warn once when a process uses split lock, but let the process
    keep running with split lock detection disabled
 3) Kill process that use split locks

Option 2 falls into the "wishful thinking" territory that Thomas warns does
nothing. But option 3 might not be viable in a situation with legacy
applications that need to run.

Hence make option 2 much stricter to "slow it down in a way which makes
it annoying".

Primary reason for this change is to provide better quality of service to
the rest of the applications running on the system. Internal testing shows
that even with many processes splitting locks, performance for the rest of
the system is much more responsive.

The new "warn" mode operates like this.  When an application tries to
execute a bus lock the #AC handler.

 1) Delays (interruptibly) 10 ms before moving to next step.

 2) Blocks (interruptibly) until it can get the semaphore
	If interrupted, just return. Assume the signal will either
	kill the task, or direct execution away from the instruction
	that is trying to get the bus lock.
 3) Disables split lock detection for the current core
 4) Schedules a work queue to re-enable split lock detect in 2 jiffies
 5) Returns

The work queue that re-enables split lock detection also releases the
semaphore.

There is a corner case where a CPU may be taken offline while split lock
detection is disabled. A CPU hotplug handler handles this case.

Old behaviour was to only print the split lock warning on the first
occurrence of a split lock from a task. Preserve that by adding a flag to
the task structure that suppresses subsequent split lock messages from that
task.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220310204854.31752-2-tony.luck@intel.com
2022-04-27 15:43:38 +02:00
Mark-PK Tsai 6621a70046 tracing: make tracer_init_tracefs initcall asynchronous
Move trace_eval_init() to subsys_initcall to make it start
earlier.
And to avoid tracer_init_tracefs being blocked by
trace_event_sem which trace_eval_init() hold [1],
queue tracer_init_tracefs() to eval_map_wq to let
the two works being executed sequentially.

It can speed up the initialization of kernel as result
of making tracer_init_tracefs asynchronous.

On my arm64 platform, it reduce ~20ms of 125ms which total
time do_initcalls spend.

Link: https://lkml.kernel.org/r/20220426122407.17042-3-mark-pk.tsai@mediatek.com

[1]: https://lore.kernel.org/r/68d7b3327052757d0cd6359a6c9015a85b437232.camel@pengutronix.de
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Mark-PK Tsai ef9188bcc6 tracing: Avoid adding tracer option before update_tracer_options
To prepare for support asynchronous tracer_init_tracefs initcall,
avoid calling create_trace_option_files before __update_tracer_options.
Otherwise, create_trace_option_files will show warning because
some tracers in trace_types list are already in tr->topts.

For example, hwlat_tracer call register_tracer in late_initcall,
and global_trace.dir is already created in tracing_init_dentry,
hwlat_tracer will be put into tr->topts.
Then if the __update_tracer_options is executed after hwlat_tracer
registered, create_trace_option_files find that hwlat_tracer is
already in tr->topts.

Link: https://lkml.kernel.org/r/20220426122407.17042-2-mark-pk.tsai@mediatek.com

Link: https://lore.kernel.org/lkml/20220322133339.GA32582@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Wan Jiabing ed888241a0 ring-buffer: Simplify if-if to if-else
Use if and else instead of if(A) and if (!A).

Link: https://lkml.kernel.org/r/20220426070628.167565-1-wanjiabing@vivo.com

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Guo Zhengkui 4ee51101e9 tracing: Use WARN instead of printk and WARN_ON
Use `WARN(cond, ...)` instead of `if (cond)` + `printk(...)` +
`WARN_ON(1)`.

Link: https://lkml.kernel.org/r/20220424131932.3606-1-guozhengkui@vivo.com

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Guo Zhengkui <guozhengkui@vivo.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Jun Miao 12025abdc8 tracing: Fix sleeping function called from invalid context on RT kernel
When setting bootparams="trace_event=initcall:initcall_start tp_printk=1" in the
cmdline, the output_printk() was called, and the spin_lock_irqsave() was called in the
atomic and irq disable interrupt context suitation. On the PREEMPT_RT kernel,
these locks are replaced with sleepable rt-spinlock, so the stack calltrace will
be triggered.
Fix it by raw_spin_lock_irqsave when PREEMPT_RT and "trace_event=initcall:initcall_start
tp_printk=1" enabled.

 BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
 preempt_count: 2, expected: 0
 RCU nest depth: 0, expected: 0
 Preemption disabled at:
 [<ffffffff8992303e>] try_to_wake_up+0x7e/0xba0
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.1-rt17+ #19 34c5812404187a875f32bee7977f7367f9679ea7
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x60/0x8c
  dump_stack+0x10/0x12
  __might_resched.cold+0x11d/0x155
  rt_spin_lock+0x40/0x70
  trace_event_buffer_commit+0x2fa/0x4c0
  ? map_vsyscall+0x93/0x93
  trace_event_raw_event_initcall_start+0xbe/0x110
  ? perf_trace_initcall_finish+0x210/0x210
  ? probe_sched_wakeup+0x34/0x40
  ? ttwu_do_wakeup+0xda/0x310
  ? trace_hardirqs_on+0x35/0x170
  ? map_vsyscall+0x93/0x93
  do_one_initcall+0x217/0x3c0
  ? trace_event_raw_event_initcall_level+0x170/0x170
  ? push_cpu_stop+0x400/0x400
  ? cblist_init_generic+0x241/0x290
  kernel_init_freeable+0x1ac/0x347
  ? _raw_spin_unlock_irq+0x65/0x80
  ? rest_init+0xf0/0xf0
  kernel_init+0x1e/0x150
  ret_from_fork+0x22/0x30
  </TASK>

Link: https://lkml.kernel.org/r/20220419013910.894370-1-jun.miao@intel.com

Signed-off-by: Jun Miao <jun.miao@intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Ammar Faizi 69686fcbdc tracing: Change `if (strlen(glob))` to `if (glob[0])`
No need to traverse to the end of string. If the first byte is not a NUL
char, it's guaranteed `if (strlen(glob))` is true.

Link: https://lkml.kernel.org/r/20220417185630.199062-3-ammarfaizi2@gnuweeb.org

Cc: Ingo Molnar <mingo@redhat.com>
Cc: GNU/Weeb Mailing List <gwml@vger.gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Ammar Faizi 97a5d2e5e3 tracing: Return -EINVAL if WARN_ON(!glob) triggered in event_hist_trigger_parse()
If `WARN_ON(!glob)` is ever triggered, we will still continue executing
the next lines. This will trigger the more serious problem, a NULL
pointer dereference bug.

Just return -EINVAL if @glob is NULL.

Link: https://lkml.kernel.org/r/20220417185630.199062-2-ammarfaizi2@gnuweeb.org

Cc: Ingo Molnar <mingo@redhat.com>
Cc: GNU/Weeb Mailing List <gwml@vger.gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Jeff Xie cb1c45fb68 tracing: Make tp_printk work on syscall tracepoints
Currently the tp_printk option has no effect on syscall tracepoint.
When adding the kernel option parameter tp_printk, then:

echo 1 > /sys/kernel/debug/tracing/events/syscalls/enable

When running any application, no trace information is printed on the
terminal.

Now added printk for syscall tracepoints.

Link: https://lkml.kernel.org/r/20220410145025.681144-1-xiehuan09@gmail.com

Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:52 -04:00
Yang Li adaa0a9f06 tracing: Fix tracing_map_sort_entries() kernel-doc comment
Add the description of @n_sort_keys and make @sort_key ->
@sort_keys in tracing_map_sort_entries() kernel-doc comment
to remove warnings found by running scripts/kernel-doc, which
is caused by using 'make W=1'.

kernel/trace/tracing_map.c:1073: warning: Function parameter or member
'sort_keys' not described in 'tracing_map_sort_entries'
kernel/trace/tracing_map.c:1073: warning: Function parameter or member
'n_sort_keys' not described in 'tracing_map_sort_entries'
kernel/trace/tracing_map.c:1073: warning: Excess function parameter
'sort_key' description in 'tracing_map_sort_entries'

Link: https://lkml.kernel.org/r/20220402072015.45864-1-yang.lee@linux.alibaba.com

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:51 -04:00
Jiapeng Chong 3b57d8477c tracing: Fix kernel-doc
Fix the following W=1 kernel warnings:

kernel/trace/trace.c:1181: warning: expecting prototype for
tracing_snapshot_cond_data(). Prototype was for
tracing_cond_snapshot_data() instead.

Link: https://lkml.kernel.org/r/20220218100849.122038-1-jiapeng.chong@linux.alibaba.com

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:51 -04:00
Oscar Shiang cf2adec747 tracing: Fix inconsistent style of mini-HOWTO
Each description should start with a hyphen and a space. Insert
spaces to fix it.

Link: https://lkml.kernel.org/r/TYCP286MB19130AA4A9C6FC5A8793DED2A1359@TYCP286MB1913.JPNP286.PROD.OUTLOOK.COM

Signed-off-by: Oscar Shiang <oscar0225@livemail.tw>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:51 -04:00
Tom Zanussi a7e6b7dcfb tracing: Separate hist state updates from hist registration
hist_register_trigger() handles both new hist registration as well as
existing hist registration through event_command.reg().

Adding a new function, existing_hist_update_only(), that checks and
updates existing histograms and exits after doing so allows the
confusing logic in event_hist_trigger_parse() to be simplified.

Link: https://lkml.kernel.org/r/211b2cd3e3d7e00f4f8ad45ef8b33063da6a7e05.1644010576.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:50 -04:00
Tom Zanussi e1f187d09e tracing: Have existing event_command.parse() implementations use helpers
Simplify the existing event_command.parse() implementations by having
them make use of the helper functions previously introduced.

Link: https://lkml.kernel.org/r/b353e3427a81f9d3adafd98fd7d73e78a8209f43.1644010576.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:50 -04:00
Tom Zanussi 4767054195 tracing: Remove redundant trigger_ops params
Since event_trigger_data contains the .ops trigger_ops field, there's
no reason to pass the trigger_ops separately. Remove it as a param
from functions whenever event_trigger_data is passed.

Link: https://lkml.kernel.org/r/9856c9bc81bde57077f5b8d6f8faa47156c6354a.1644010575.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:50 -04:00
Tom Zanussi b8cc44a4d3 tracing: Remove logic for registering multiple event triggers at a time
Code for registering triggers assumes it's possible to register more
than one trigger at a time.  In fact, it's unimplemented and there
doesn't seem to be a reason to do that.

Remove the n_registered param from event_trigger_register() and fix up
callers.

Doing so simplifies the logic in event_trigger_register to the point
that it just becomes a wrapper calling event_command.reg().

It also removes the problematic call to event_command.unreg() in case
of failure.  A new function, event_trigger_unregister() is also added
for callers to call themselves.

The changes to trace_events_hist.c simply allow compilation; a
separate patch follows which updates the hist triggers to work
correctly with the new changes.

Link: https://lkml.kernel.org/r/6149fec7a139d93e84fa4535672fb5bef88006b0.1644010575.git.zanussi@kernel.org

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:50 -04:00
Tom Rix 217d8c05ec tracing: Cleanup double word in comment
Remove the second 'is' and 'to'.

Link: https://lkml.kernel.org/r/20220207131216.2059997-1-trix@redhat.com

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-26 17:58:50 -04:00
Menglong Dong c317ab71fa bpf: Compute map_btf_id during build time
For now, the field 'map_btf_id' in 'struct bpf_map_ops' for all map
types are computed during vmlinux-btf init:

  btf_parse_vmlinux() -> btf_vmlinux_map_ids_init()

It will lookup the btf_type according to the 'map_btf_name' field in
'struct bpf_map_ops'. This process can be done during build time,
thanks to Jiri's resolve_btfids.

selftest of map_ptr has passed:

  $96 map_ptr:OK
  Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2022-04-26 11:35:21 -07:00
Adam Zabrocki 1d661ed54d kprobes: Fix KRETPROBES when CONFIG_KRETPROBE_ON_RETHOOK is set
The recent kernel change in 73f9b911fa ("kprobes: Use rethook for kretprobe
if possible"), introduced a potential NULL pointer dereference bug in the
KRETPROBE mechanism. The official Kprobes documentation defines that "Any or
all handlers can be NULL". Unfortunately, there is a missing return handler
verification to fulfill these requirements and can result in a NULL pointer
dereference bug.

This patch adds such verification in kretprobe_rethook_handler() function.

Fixes: 73f9b911fa ("kprobes: Use rethook for kretprobe if possible")
Signed-off-by: Adam Zabrocki <pi3@pi3.com.pl>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Anil S. Keshavamurthy <anil.s.keshavamurthy@intel.com>
Link: https://lore.kernel.org/bpf/20220422164027.GA7862@pi3.com.pl
2022-04-26 16:09:36 +02:00
John Ogness ab406816fc printk: remove @console_locked
The static global variable @console_locked is used to help debug
VT code to make sure that certain code paths are running with
the console_lock held. However, this information is also available
with the static global variable @console_kthreads_blocked (for
locking via console_lock()), and the static global variable
@console_kthreads_active (for locking via console_trylock()).

Remove @console_locked and update is_console_locked() to use the
alternative variables.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-16-john.ogness@linutronix.de
2022-04-26 14:33:59 +02:00
John Ogness 8e27473211 printk: extend console_lock for per-console locking
Currently threaded console printers synchronize against each
other using console_lock(). However, different console drivers
are unrelated and do not require any synchronization between
each other. Removing the synchronization between the threaded
console printers will allow each console to print at its own
speed.

But the threaded consoles printers do still need to synchronize
against console_lock() callers. Introduce a per-console mutex
and a new console boolean field @blocked to provide this
synchronization.

console_lock() is modified so that it must acquire the mutex
of each console in order to set the @blocked field. Console
printing threads will acquire their mutex while printing a
record. If @blocked was set, the thread will go back to sleep
instead of printing.

The reason for the @blocked boolean field is so that
console_lock() callers do not need to acquire multiple console
mutexes simultaneously, which would introduce unnecessary
complexity due to nested mutex locking. Also, a new field
was chosen instead of adding a new @flags value so that the
blocked status could be checked without concern of reading
inconsistent values due to @flags updates from other contexts.

Threaded console printers also need to synchronize against
console_trylock() callers. Since console_trylock() may be
called from any context, the per-console mutex cannot be used
for this synchronization. (mutex_trylock() cannot be called
from atomic contexts.) Introduce a global atomic counter to
identify if any threaded printers are active. The threaded
printers will also check the atomic counter to identify if the
console has been locked by another task via console_trylock().

Note that @console_sem is still used to provide synchronization
between console_lock() and console_trylock() callers.

A locking overview for console_lock(), console_trylock(), and the
threaded printers is as follows (pseudo code):

console_lock()
{
        down(&console_sem);
        for_each_console(con) {
                mutex_lock(&con->lock);
                con->blocked = true;
                mutex_unlock(&con->lock);
        }
        /* console_lock acquired */
}

console_trylock()
{
        if (down_trylock(&console_sem) == 0) {
                if (atomic_cmpxchg(&console_kthreads_active, 0, -1) == 0) {
                        /* console_lock acquired */
                }
        }
}

threaded_printer()
{
        mutex_lock(&con->lock);
        if (!con->blocked) {
		/* console_lock() callers blocked */

                if (atomic_inc_unless_negative(&console_kthreads_active)) {
                        /* console_trylock() callers blocked */

                        con->write();

                        atomic_dec(&console_lock_count);
                }
        }
        mutex_unlock(&con->lock);
}

The console owner and waiter logic now only applies between contexts
that have taken the console_lock via console_trylock(). Threaded
printers never take the console_lock, so they do not have a
console_lock to handover. Tasks that have used console_lock() will
block the threaded printers using a mutex and if the console_lock
is handed over to an atomic context, it would be unable to unblock
the threaded printers. However, the console_trylock() case is
really the only scenario that is interesting for handovers anyway.

@panic_console_dropped must change to atomic_t since it is no longer
protected exclusively by the console_lock.

Since threaded printers remain asleep if they see that the console
is locked, they now must be explicitly woken in __console_unlock().
This means wake_up_klogd() calls following a console_unlock() are
no longer necessary and are removed.

Also note that threaded printers no longer need to check
@console_suspended. The check for the @blocked field implicitly
covers the suspended console case.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/878rrs6ft7.fsf@jogness.linutronix.de
2022-04-26 14:32:00 +02:00
Kumar Kartikeya Dwivedi 2ab3b3808e bpf: Make BTF type match stricter for release arguments
The current of behavior of btf_struct_ids_match for release arguments is
that when type match fails, it retries with first member type again
(recursively). Since the offset is already 0, this is akin to just
casting the pointer in normal C, since if type matches it was just
embedded inside parent sturct as an object. However, we want to reject
cases for release function type matching, be it kfunc or BPF helpers.

An example is the following:

struct foo {
	struct bar b;
};

struct foo *v = acq_foo();
rel_bar(&v->b); // btf_struct_ids_match fails btf_types_are_same, then
		// retries with first member type and succeeds, while
		// it should fail.

Hence, don't walk the struct and only rely on btf_types_are_same for
strict mode. All users of strict mode must be dealing with zero offset
anyway, since otherwise they would want the struct to be walked.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-10-memxor@gmail.com
2022-04-25 20:26:44 -07:00
Kumar Kartikeya Dwivedi a1ef195996 bpf: Teach verifier about kptr_get kfunc helpers
We introduce a new style of kfunc helpers, namely *_kptr_get, where they
take pointer to the map value which points to a referenced kernel
pointer contained in the map. Since this is referenced, only
bpf_kptr_xchg from BPF side and xchg from kernel side is allowed to
change the current value, and each pointer that resides in that location
would be referenced, and RCU protected (this must be kept in mind while
adding kernel types embeddable as reference kptr in BPF maps).

This means that if do the load of the pointer value in an RCU read
section, and find a live pointer, then as long as we hold RCU read lock,
it won't be freed by a parallel xchg + release operation. This allows us
to implement a safe refcount increment scheme. Hence, enforce that first
argument of all such kfunc is a proper PTR_TO_MAP_VALUE pointing at the
right offset to referenced pointer.

For the rest of the arguments, they are subjected to typical kfunc
argument checks, hence allowing some flexibility in passing more intent
into how the reference should be taken.

For instance, in case of struct nf_conn, it is not freed until RCU grace
period ends, but can still be reused for another tuple once refcount has
dropped to zero. Hence, a bpf_ct_kptr_get helper not only needs to call
refcount_inc_not_zero, but also do a tuple match after incrementing the
reference, and when it fails to match it, put the reference again and
return NULL.

This can be implemented easily if we allow passing additional parameters
to the bpf_ct_kptr_get kfunc, like a struct bpf_sock_tuple * and a
tuple__sz pair.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-9-memxor@gmail.com
2022-04-25 20:26:44 -07:00
Kumar Kartikeya Dwivedi 14a324f6a6 bpf: Wire up freeing of referenced kptr
A destructor kfunc can be defined as void func(type *), where type may
be void or any other pointer type as per convenience.

In this patch, we ensure that the type is sane and capture the function
pointer into off_desc of ptr_off_tab for the specific pointer offset,
with the invariant that the dtor pointer is always set when 'kptr_ref'
tag is applied to the pointer's pointee type, which is indicated by the
flag BPF_MAP_VALUE_OFF_F_REF.

Note that only BTF IDs whose destructor kfunc is registered, thus become
the allowed BTF IDs for embedding as referenced kptr. Hence it serves
the purpose of finding dtor kfunc BTF ID, as well acting as a check
against the whitelist of allowed BTF IDs for this purpose.

Finally, wire up the actual freeing of the referenced pointer if any at
all available offsets, so that no references are leaked after the BPF
map goes away and the BPF program previously moved the ownership a
referenced pointer into it.

The behavior is similar to BPF timers, where bpf_map_{update,delete}_elem
will free any existing referenced kptr. The same case is with LRU map's
bpf_lru_push_free/htab_lru_push_free functions, which are extended to
reset unreferenced and free referenced kptr.

Note that unlike BPF timers, kptr is not reset or freed when map uref
drops to zero.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-8-memxor@gmail.com
2022-04-25 20:26:44 -07:00
Kumar Kartikeya Dwivedi 5ce937d613 bpf: Populate pairs of btf_id and destructor kfunc in btf
To support storing referenced PTR_TO_BTF_ID in maps, we require
associating a specific BTF ID with a 'destructor' kfunc. This is because
we need to release a live referenced pointer at a certain offset in map
value from the map destruction path, otherwise we end up leaking
resources.

Hence, introduce support for passing an array of btf_id, kfunc_btf_id
pairs that denote a BTF ID and its associated release function. Then,
add an accessor 'btf_find_dtor_kfunc' which can be used to look up the
destructor kfunc of a certain BTF ID. If found, we can use it to free
the object from the map free path.

The registration of these pairs also serve as a whitelist of structures
which are allowed as referenced PTR_TO_BTF_ID in a BPF map, because
without finding the destructor kfunc, we will bail and return an error.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-7-memxor@gmail.com
2022-04-25 20:26:44 -07:00
Kumar Kartikeya Dwivedi 4d7d7f69f4 bpf: Adapt copy_map_value for multiple offset case
Since now there might be at most 10 offsets that need handling in
copy_map_value, the manual shuffling and special case is no longer going
to work. Hence, let's generalise the copy_map_value function by using
a sorted array of offsets to skip regions that must be avoided while
copying into and out of a map value.

When the map is created, we populate the offset array in struct map,
Then, copy_map_value uses this sorted offset array is used to memcpy
while skipping timer, spin lock, and kptr. The array is allocated as
in most cases none of these special fields would be present in map
value, hence we can save on space for the common case by not embedding
the entire object inside bpf_map struct.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-6-memxor@gmail.com
2022-04-25 20:26:44 -07:00
Kumar Kartikeya Dwivedi 6efe152d40 bpf: Prevent escaping of kptr loaded from maps
While we can guarantee that even for unreferenced kptr, the object
pointer points to being freed etc. can be handled by the verifier's
exception handling (normal load patching to PROBE_MEM loads), we still
cannot allow the user to pass these pointers to BPF helpers and kfunc,
because the same exception handling won't be done for accesses inside
the kernel. The same is true if a referenced pointer is loaded using
normal load instruction. Since the reference is not guaranteed to be
held while the pointer is used, it must be marked as untrusted.

Hence introduce a new type flag, PTR_UNTRUSTED, which is used to mark
all registers loading unreferenced and referenced kptr from BPF maps,
and ensure they can never escape the BPF program and into the kernel by
way of calling stable/unstable helpers.

In check_ptr_to_btf_access, the !type_may_be_null check to reject type
flags is still correct, as apart from PTR_MAYBE_NULL, only MEM_USER,
MEM_PERCPU, and PTR_UNTRUSTED may be set for PTR_TO_BTF_ID. The first
two are checked inside the function and rejected using a proper error
message, but we still want to allow dereference of untrusted case.

Also, we make sure to inherit PTR_UNTRUSTED when chain of pointers are
walked, so that this flag is never dropped once it has been set on a
PTR_TO_BTF_ID (i.e. trusted to untrusted transition can only be in one
direction).

In convert_ctx_accesses, extend the switch case to consider untrusted
PTR_TO_BTF_ID in addition to normal PTR_TO_BTF_ID for PROBE_MEM
conversion for BPF_LDX.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-5-memxor@gmail.com
2022-04-25 20:26:44 -07:00
Kumar Kartikeya Dwivedi c0a5a21c25 bpf: Allow storing referenced kptr in map
Extending the code in previous commits, introduce referenced kptr
support, which needs to be tagged using 'kptr_ref' tag instead. Unlike
unreferenced kptr, referenced kptr have a lot more restrictions. In
addition to the type matching, only a newly introduced bpf_kptr_xchg
helper is allowed to modify the map value at that offset. This transfers
the referenced pointer being stored into the map, releasing the
references state for the program, and returning the old value and
creating new reference state for the returned pointer.

Similar to unreferenced pointer case, return value for this case will
also be PTR_TO_BTF_ID_OR_NULL. The reference for the returned pointer
must either be eventually released by calling the corresponding release
function, otherwise it must be transferred into another map.

It is also allowed to call bpf_kptr_xchg with a NULL pointer, to clear
the value, and obtain the old value if any.

BPF_LDX, BPF_STX, and BPF_ST cannot access referenced kptr. A future
commit will permit using BPF_LDX for such pointers, but attempt at
making it safe, since the lifetime of object won't be guaranteed.

There are valid reasons to enforce the restriction of permitting only
bpf_kptr_xchg to operate on referenced kptr. The pointer value must be
consistent in face of concurrent modification, and any prior values
contained in the map must also be released before a new one is moved
into the map. To ensure proper transfer of this ownership, bpf_kptr_xchg
returns the old value, which the verifier would require the user to
either free or move into another map, and releases the reference held
for the pointer being moved in.

In the future, direct BPF_XCHG instruction may also be permitted to work
like bpf_kptr_xchg helper.

Note that process_kptr_func doesn't have to call
check_helper_mem_access, since we already disallow rdonly/wronly flags
for map, which is what check_map_access_type checks, and we already
ensure the PTR_TO_MAP_VALUE refers to kptr by obtaining its off_desc,
so check_map_access is also not required.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-4-memxor@gmail.com
2022-04-25 20:26:05 -07:00
Kumar Kartikeya Dwivedi 8f14852e89 bpf: Tag argument to be released in bpf_func_proto
Add a new type flag for bpf_arg_type that when set tells verifier that
for a release function, that argument's register will be the one for
which meta.ref_obj_id will be set, and which will then be released
using release_reference. To capture the regno, introduce a new field
release_regno in bpf_call_arg_meta.

This would be required in the next patch, where we may either pass NULL
or a refcounted pointer as an argument to the release function
bpf_kptr_xchg. Just releasing only when meta.ref_obj_id is set is not
enough, as there is a case where the type of argument needed matches,
but the ref_obj_id is set to 0. Hence, we must enforce that whenever
meta.ref_obj_id is zero, the register that is to be released can only
be NULL for a release function.

Since we now indicate whether an argument is to be released in
bpf_func_proto itself, is_release_function helper has lost its utitlity,
hence refactor code to work without it, and just rely on
meta.release_regno to know when to release state for a ref_obj_id.
Still, the restriction of one release argument and only one ref_obj_id
passed to BPF helper or kfunc remains. This may be lifted in the future.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-3-memxor@gmail.com
2022-04-25 17:31:35 -07:00
Kumar Kartikeya Dwivedi 61df10c779 bpf: Allow storing unreferenced kptr in map
This commit introduces a new pointer type 'kptr' which can be embedded
in a map value to hold a PTR_TO_BTF_ID stored by a BPF program during
its invocation. When storing such a kptr, BPF program's PTR_TO_BTF_ID
register must have the same type as in the map value's BTF, and loading
a kptr marks the destination register as PTR_TO_BTF_ID with the correct
kernel BTF and BTF ID.

Such kptr are unreferenced, i.e. by the time another invocation of the
BPF program loads this pointer, the object which the pointer points to
may not longer exist. Since PTR_TO_BTF_ID loads (using BPF_LDX) are
patched to PROBE_MEM loads by the verifier, it would safe to allow user
to still access such invalid pointer, but passing such pointers into
BPF helpers and kfuncs should not be permitted. A future patch in this
series will close this gap.

The flexibility offered by allowing programs to dereference such invalid
pointers while being safe at runtime frees the verifier from doing
complex lifetime tracking. As long as the user may ensure that the
object remains valid, it can ensure data read by it from the kernel
object is valid.

The user indicates that a certain pointer must be treated as kptr
capable of accepting stores of PTR_TO_BTF_ID of a certain type, by using
a BTF type tag 'kptr' on the pointed to type of the pointer. Then, this
information is recorded in the object BTF which will be passed into the
kernel by way of map's BTF information. The name and kind from the map
value BTF is used to look up the in-kernel type, and the actual BTF and
BTF ID is recorded in the map struct in a new kptr_off_tab member. For
now, only storing pointers to structs is permitted.

An example of this specification is shown below:

	#define __kptr __attribute__((btf_type_tag("kptr")))

	struct map_value {
		...
		struct task_struct __kptr *task;
		...
	};

Then, in a BPF program, user may store PTR_TO_BTF_ID with the type
task_struct into the map, and then load it later.

Note that the destination register is marked PTR_TO_BTF_ID_OR_NULL, as
the verifier cannot know whether the value is NULL or not statically, it
must treat all potential loads at that map value offset as loading a
possibly NULL pointer.

Only BPF_LDX, BPF_STX, and BPF_ST (with insn->imm = 0 to denote NULL)
are allowed instructions that can access such a pointer. On BPF_LDX, the
destination register is updated to be a PTR_TO_BTF_ID, and on BPF_STX,
it is checked whether the source register type is a PTR_TO_BTF_ID with
same BTF type as specified in the map BTF. The access size must always
be BPF_DW.

For the map in map support, the kptr_off_tab for outer map is copied
from the inner map's kptr_off_tab. It was chosen to do a deep copy
instead of introducing a refcount to kptr_off_tab, because the copy only
needs to be done when paramterizing using inner_map_fd in the map in map
case, hence would be unnecessary for all other users.

It is not permitted to use MAP_FREEZE command and mmap for BPF map
having kptrs, similar to the bpf_timer case. A kptr also requires that
BPF program has both read and write access to the map (hence both
BPF_F_RDONLY_PROG and BPF_F_WRONLY_PROG are disallowed).

Note that check_map_access must be called from both
check_helper_mem_access and for the BPF instructions, hence the kptr
check must distinguish between ACCESS_DIRECT and ACCESS_HELPER, and
reject ACCESS_HELPER cases. We rename stack_access_src to bpf_access_src
and reuse it for this purpose.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-2-memxor@gmail.com
2022-04-25 17:31:35 -07:00
Stanislav Fomichev d9d31cf887 bpf: Use bpf_prog_run_array_cg_flags everywhere
Rename bpf_prog_run_array_cg_flags to bpf_prog_run_array_cg and
use it everywhere. check_return_code already enforces sane
return ranges for all cgroup types. (only egress and bind hooks have
uncanonical return ranges, the rest is using [0, 1])

No functional changes.

v2:
- 'func_ret & 1' under explicit test (Andrii & Martin)

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220425220448.3669032-1-sdf@google.com
2022-04-25 17:03:57 -07:00
yingelin a467257ffe kernel/kexec_core: move kexec_core sysctls into its own file
This move the kernel/kexec_core.c respective sysctls to its own file.

kernel/sysctl.c has grown to an insane mess, We move sysctls to places
where features actually belong to improve the readability and reduce
merge conflicts. At the same time, the proc-sysctl maintainers can easily
care about the core logic other than the sysctl knobs added for some feature.

We already moved all filesystem sysctls out. This patch is part of the effort
to move kexec related sysctls out.

Signed-off-by: yingelin <yingelin@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-04-25 14:01:11 -07:00
Colin Ian King 1adb4d7ad3 genirq/matrix: Remove redundant assignment to variable 'end'
Variable end is being initialized with a value that is never read, it
is being re-assigned later with the same value. The initialization is
redundant and can be removed.

Cleans up clang scan build warning:
kernel/irq/matrix.c:289:25: warning: Value stored to 'end' during its
initialization is never read [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20220422110418.1264778-1-colin.i.king@gmail.com
2022-04-25 15:02:57 +02:00
Nicholas Piggin 62c1256d54 timers/nohz: Switch to ONESHOT_STOPPED in the low-res handler when the tick is stopped
When tick_nohz_stop_tick() stops the tick and high resolution timers are
disabled, then the clock event device is not put into ONESHOT_STOPPED
mode. This can lead to spurious timer interrupts with some clock event
device drivers that don't shut down entirely after firing.

Eliminate these by putting the device into ONESHOT_STOPPED mode at points
where it is not being reprogrammed. When there are no timers active, then
tick_program_event() with KTIME_MAX can be used to stop the device. When
there is a timer active, the device can be stopped at the next tick (any
new timer added by timers will reprogram the tick).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220422141446.915024-1-npiggin@gmail.com
2022-04-25 14:45:22 +02:00
Amir Goldstein 960bdff24c audit: use fsnotify group lock helpers
audit inode marks pin the inode so there is no need to set the
FSNOTIFY_GROUP_NOFS flag.

Link: https://lore.kernel.org/r/20220422120327.3459282-9-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220321112310.vpr7oxro2xkz5llh@quack3.lan/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2022-04-25 14:37:28 +02:00
Amir Goldstein f3010343d9 fsnotify: make allow_dups a property of the group
Instead of passing the allow_dups argument to fsnotify_add_mark()
as an argument, define the group flag FSNOTIFY_GROUP_DUPS to express
the allow_dups behavior and set this behavior at group creation time
for all calls of fsnotify_add_mark().

Rename the allow_dups argument to generic add_flags argument for future
use.

Link: https://lore.kernel.org/r/20220422120327.3459282-6-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2022-04-25 14:37:18 +02:00
Amir Goldstein 867a448d58 fsnotify: pass flags argument to fsnotify_alloc_group()
Add flags argument to fsnotify_alloc_group(), define and use the flag
FSNOTIFY_GROUP_USER in inotify and fanotify instead of the helper
fsnotify_alloc_user_group() to indicate user allocation.

Although the flag FSNOTIFY_GROUP_USER is currently not used after group
allocation, we store the flags argument in the group struct for future
use of other group flags.

Link: https://lore.kernel.org/r/20220422120327.3459282-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2022-04-25 14:37:12 +02:00
Linus Torvalds 42740a2ff5 - Fix a corner case when calculating sched runqueue variables
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Merge tag 'sched_urgent_for_v5.18_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fix from Borislav Petkov:

 - Fix a corner case when calculating sched runqueue variables

That fix also removes a check for a zero divisor in the code, without
mentioning it.  Vincent clarified that it's ok after I whined about it:

  https://lore.kernel.org/all/CAKfTPtD2QEyZ6ADd5WrwETMOX0XOwJGnVddt7VHgfURdqgOS-Q@mail.gmail.com/

* tag 'sched_urgent_for_v5.18_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/pelt: Fix attach_entity_load_avg() corner case
2022-04-24 13:28:06 -07:00
Linus Torvalds f48ffef19d - Add Sapphire Rapids CPU support
- Fix a perf vmalloc-ed buffer mapping error (PERF_USE_VMALLOC in use)
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Merge tag 'perf_urgent_for_v5.18_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Borislav Petkov:

 - Add Sapphire Rapids CPU support

 - Fix a perf vmalloc-ed buffer mapping error (PERF_USE_VMALLOC in use)

* tag 'perf_urgent_for_v5.18_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/cstate: Add SAPPHIRERAPIDS_X CPU support
  perf/core: Fix perf_mmap fail when CONFIG_PERF_USE_VMALLOC enabled
2022-04-24 12:01:16 -07:00
Dan Williams 9ea4dcf498 PM: CXL: Disable suspend
The CXL specification claims S3 support at a hardware level, but at a
system software level there are some missing pieces. Section 9.4 (CXL
2.0) rightly claims that "CXL mem adapters may need aux power to retain
memory context across S3", but there is no enumeration mechanism for the
OS to determine if a given adapter has that support. Moreover the save
state and resume image for the system may inadvertantly end up in a CXL
device that needs to be restored before the save state is recoverable.
I.e. a circular dependency that is not resolvable without a third party
save-area.

Arrange for the cxl_mem driver to fail S3 attempts. This still nominaly
allows for suspend, but requires unbinding all CXL memory devices before
the suspend to ensure the typical DRAM flow is taken. The cxl_mem unbind
flow is intended to also tear down all CXL memory regions associated
with a given cxl_memdev.

It is reasonable to assume that any device participating in a System RAM
range published in the EFI memory map is covered by aux power and
save-area outside the device itself. So this restriction can be
minimized in the future once pre-existing region enumeration support
arrives, and perhaps a spec update to clarify if the EFI memory map is
sufficent for determining the range of devices managed by
platform-firmware for S3 support.

Per Rafael, if the CXL configuration prevents suspend then it should
fail early before tasks are frozen, and mem_sleep should stop showing
'mem' as an option [1]. Effectively CXL augments the platform suspend
->valid() op since, for example, the ACPI ops are not aware of the CXL /
PCI dependencies. Given the split role of platform firmware vs OS
provisioned CXL memory it is up to the cxl_mem driver to determine if
the CXL configuration has elements that platform firmware may not be
prepared to restore.

Link: https://lore.kernel.org/r/CAJZ5v0hGVN_=3iU8OLpHY3Ak35T5+JcBM-qs8SbojKrpd0VXsA@mail.gmail.com [1]
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/165066828317.3907920.5690432272182042556.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2022-04-22 16:09:42 -07:00
Andrii Nakryiko df86ca0d2f bpf: Allow attach TRACING programs through LINK_CREATE command
Allow attaching BTF-aware TRACING programs, previously attachable only
through BPF_RAW_TRACEPOINT_OPEN command, through LINK_CREATE command:

  - BTF-aware raw tracepoints (tp_btf in libbpf lingo);
  - fentry/fexit/fmod_ret programs;
  - BPF LSM programs.

This change converges all bpf_link-based attachments under LINK_CREATE
command allowing to further extend the API with features like BPF cookie
under "multiplexed" link_create section of bpf_attr.

Non-BTF-aware raw tracepoints are left under BPF_RAW_TRACEPOINT_OPEN,
but there is nothing preventing opening them up to LINK_CREATE as well.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Kuifeng Lee <kuifeng@fb.com>
Link: https://lore.kernel.org/bpf/20220421033945.3602803-2-andrii@kernel.org
2022-04-23 00:36:55 +02:00
John Ogness 09c5ba0aa2 printk: add kthread console printers
Create a kthread for each console to perform console printing. During
normal operation (@system_state == SYSTEM_RUNNING), the kthread
printers are responsible for all printing on their respective
consoles.

During non-normal operation, console printing is done as it has been:
within the context of the printk caller or within irqwork triggered
by the printk caller, referred to as direct printing.

Since threaded console printers are responsible for all printing
during normal operation, this also includes messages generated via
deferred printk calls. If direct printing is in effect during a
deferred printk call, the queued irqwork will perform the direct
printing. To make it clear that this is the only time that the
irqwork will perform direct printing, rename the flag
PRINTK_PENDING_OUTPUT to PRINTK_PENDING_DIRECT_OUTPUT.

Threaded console printers synchronize against each other and against
console lockers by taking the console lock for each message that is
printed.

Note that the kthread printers do not care about direct printing.
They will always try to print if new records are available. They can
be blocked by direct printing, but will be woken again once direct
printing is finished.

Console unregistration is a bit tricky because the associated
kthread printer cannot be stopped while the console lock is held.
A policy is implemented that states: whichever task clears
con->thread (under the console lock) is responsible for stopping
the kthread. unregister_console() will clear con->thread while
the console lock is held and then stop the kthread after releasing
the console lock.

For consoles that have implemented the exit() callback, the kthread
is stopped before exit() is called.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-14-john.ogness@linutronix.de
2022-04-22 21:30:58 +02:00
John Ogness 2bb2b7b57f printk: add functions to prefer direct printing
Once kthread printing is available, console printing will no longer
occur in the context of the printk caller. However, there are some
special contexts where it is desirable for the printk caller to
directly print out kernel messages. Using pr_flush() to wait for
threaded printers is only possible if the caller is in a sleepable
context and the kthreads are active. That is not always the case.

Introduce printk_prefer_direct_enter() and printk_prefer_direct_exit()
functions to explicitly (and globally) activate/deactivate preferred
direct console printing. The term "direct console printing" refers to
printing to all enabled consoles from the context of the printk
caller. The term "prefer" is used because this type of printing is
only best effort. If the console is currently locked or other
printers are already actively printing, the printk caller will need
to rely on the other contexts to handle the printing.

This preferred direct printing is how all printing has been handled
until now (unless it was explicitly deferred).

When kthread printing is introduced, there may be some unanticipated
problems due to kthreads being unable to flush important messages.
In order to minimize such risks, preferred direct printing is
activated for the primary important messages when the system
experiences general types of major errors. These are:

 - emergency reboot/shutdown
 - cpu and rcu stalls
 - hard and soft lockups
 - hung tasks
 - warn
 - sysrq

Note that since kthread printing does not yet exist, no behavior
changes result from this commit. This is only implementing the
counter and marking the various places where preferred direct
printing is active.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org> # for RCU
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-13-john.ogness@linutronix.de
2022-04-22 21:30:58 +02:00
John Ogness 3b604ca812 printk: add pr_flush()
Provide a might-sleep function to allow waiting for console printers
to catch up to the latest logged message.

Use pr_flush() whenever it is desirable to get buffered messages
printed before continuing: suspend_console(), resume_console(),
console_stop(), console_start(), console_unblank().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-12-john.ogness@linutronix.de
2022-04-22 21:30:58 +02:00
John Ogness 03a749e628 printk: move buffer definitions into console_emit_next_record() caller
Extended consoles print extended messages and do not print messages about
dropped records.

Non-extended consoles print "normal" messages as well as extra messages
about dropped records.

Currently the buffers for these various message types are defined within
the functions that might use them and their usage is based upon the
CON_EXTENDED flag. This will be a problem when moving to kthread printers
because each printer must be able to provide its own buffers.

Move all the message buffer definitions outside of
console_emit_next_record(). The caller knows if extended or dropped
messages should be printed and can specify the appropriate buffers to
use. The console_emit_next_record() and call_console_driver() functions
can know what to print based on whether specified buffers are non-NULL.

With this change, buffer definition/allocation/specification is separated
from the code that does the various types of string printing.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-11-john.ogness@linutronix.de
2022-04-22 21:30:58 +02:00
John Ogness a699449bb1 printk: refactor and rework printing logic
Refactor/rework printing logic in order to prepare for moving to
threaded console printing.

- Move @console_seq into struct console so that the current
  "position" of each console can be tracked individually.

- Move @console_dropped into struct console so that the current drop
  count of each console can be tracked individually.

- Modify printing logic so that each console independently loads,
  prepares, and prints its next record.

- Remove exclusive_console logic. Since console positions are
  handled independently, replaying past records occurs naturally.

- Update the comments explaining why preemption is disabled while
  printing from printk() context.

With these changes, there is a change in behavior: the console
replaying the log (formerly exclusive console) will no longer block
other consoles. New messages appear on the other consoles while the
newly added console is still replaying.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-10-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
John Ogness 1fc0ca9e0d printk: add con_printk() macro for console details
It is useful to generate log messages that include details about
the related console. Rather than duplicate the code to assemble
the details, put that code into a macro con_printk().

Once console printers become threaded, this macro will find more
users.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-9-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
John Ogness 1f47e8af45 printk: call boot_delay_msec() in printk_delay()
boot_delay_msec() is always called immediately before printk_delay()
so just call it from within printk_delay().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-8-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
John Ogness 9f0844de49 printk: get caller_id/timestamp after migration disable
Currently the local CPU timestamp and caller_id for the record are
collected while migration is enabled. Since this information is
CPU-specific, it should be collected with migration disabled.

Migration is disabled immediately after collecting this information
anyway, so just move the information collection to after the
migration disabling.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-7-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
John Ogness 5341b93dea printk: wake waiters for safe and NMI contexts
When printk() is called from safe or NMI contexts, it will directly
store the record (vprintk_store()) and then defer the console output.
However, defer_console_output() only causes console printing and does
not wake any waiters of new records.

Wake waiters from defer_console_output() so that they also are aware
of the new records from safe and NMI contexts.

Fixes: 03fc7f9c99 ("printk/nmi: Prevent deadlock when accessing the main log buffer in NMI")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-6-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
John Ogness 938ba4084a printk: wake up all waiters
There can be multiple tasks waiting for new records. They should
all be woken. Use wake_up_interruptible_all() instead of
wake_up_interruptible().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-5-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
John Ogness 1f5d783094 printk: add missing memory barrier to wake_up_klogd()
It is important that any new records are visible to preparing
waiters before the waker checks if the wait queue is empty.
Otherwise it is possible that:

- there are new records available
- the waker sees an empty wait queue and does not wake
- the preparing waiter sees no new records and begins to wait

This is exactly the problem that the function description of
waitqueue_active() warns about.

Use wq_has_sleeper() instead of waitqueue_active() because it
includes the necessary full memory barrier.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-4-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
John Ogness faebd693c5 printk: rename cpulock functions
Since the printk cpulock is CPU-reentrant and since it is used
in all contexts, its usage must be carefully considered and
most likely will require programming locklessly. To avoid
mistaking the printk cpulock as a typical lock, rename it to
cpu_sync. The main functions then become:

    printk_cpu_sync_get_irqsave(flags);
    printk_cpu_sync_put_irqrestore(flags);

Add extra notes of caution in the function description to help
developers understand the requirements for correct usage.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-2-john.ogness@linutronix.de
2022-04-22 21:30:57 +02:00
Mark Brown 9e4ab6c891 arm64/sme: Implement vector length configuration prctl()s
As for SVE provide a prctl() interface which allows processes to
configure their SME vector length.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20220419112247.711548-12-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2022-04-22 18:50:54 +01:00
Josh Poimboeuf 03f16cd020 objtool: Add CONFIG_OBJTOOL
Now that stack validation is an optional feature of objtool, add
CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with
it.

CONFIG_STACK_VALIDATION can now be considered to be frame-pointer
specific.  CONFIG_UNWINDER_ORC is already inherently valid for live
patching, so no need to "validate" it.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com
2022-04-22 12:32:03 +02:00
Tao Zhou a658353167 sched/fair: Revise comment about lb decision matrix
If busiest group type is group_misfit_task, the local
group type must be group_has_spare according to below
code in update_sd_pick_busiest():

  if (sgs->group_type == group_misfit_task &&
      (!capacity_greater(capacity_of(env->dst_cpu), sg->sgc->max_capacity) ||
       sds->local_stat.group_type != group_has_spare))
	   return false;

group type imbalanced and overloaded and fully_busy are filtered in here.
misfit and asym are filtered before in update_sg_lb_stats().
So, change the decision matrix to:

  busiest \ local has_spare fully_busy misfit asym imbalanced overloaded
  has_spare        nr_idle   balanced   N/A    N/A  balanced   balanced
  fully_busy       nr_idle   nr_idle    N/A    N/A  balanced   balanced
  misfit_task      force     N/A        N/A    N/A  *N/A*      *N/A*
  asym_packing     force     force      N/A    N/A  force      force
  imbalanced       force     force      N/A    N/A  force      force
  overloaded       force     force      N/A    N/A  force      avg_load

Fixes: 0b0695f2b3 ("sched/fair: Rework load_balance()")
Signed-off-by: Tao Zhou <tao.zhou@linux.dev>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20220415095505.7765-1-tao.zhou@linux.dev
2022-04-22 12:14:08 +02:00
Chengming Zhou 890d550d7d sched/psi: report zeroes for CPU full at the system level
Martin find it confusing when look at the /proc/pressure/cpu output,
and found no hint about that CPU "full" line in psi Documentation.

% cat /proc/pressure/cpu
some avg10=0.92 avg60=0.91 avg300=0.73 total=933490489
full avg10=0.22 avg60=0.23 avg300=0.16 total=358783277

The PSI_CPU_FULL state is introduced by commit e7fcd76228
("psi: Add PSI_CPU_FULL state"), which mainly for cgroup level,
but also counted at the system level as a side effect.

Naturally, the FULL state doesn't exist for the CPU resource at
the system level. These "full" numbers can come from CPU idle
schedule latency. For example, t1 is the time when task wakeup
on an idle CPU, t2 is the time when CPU pick and switch to it.
The delta of (t2 - t1) will be in CPU_FULL state.

Another case all processes can be stalled is when all cgroups
have been throttled at the same time, which unlikely to happen.

Anyway, CPU_FULL metric is meaningless and confusing at the
system level. So this patch will report zeroes for CPU full
at the system level, and update psi Documentation accordingly.

Fixes: e7fcd76228 ("psi: Add PSI_CPU_FULL state")
Reported-by: Martin Steigerwald <Martin.Steigerwald@proact.de>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/r/20220408121914.82855-1-zhouchengming@bytedance.com
2022-04-22 12:14:08 +02:00
Chengming Zhou 0a00a35464 sched/fair: Delete useless condition in tg_unthrottle_up()
We have tested cfs_rq->load.weight in cfs_rq_is_decayed(),
the first condition "!cfs_rq_is_decayed(cfs_rq)" is enough
to cover the second condition "cfs_rq->nr_running".

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20220408115309.81603-2-zhouchengming@bytedance.com
2022-04-22 12:14:07 +02:00
Chengming Zhou 64eaf50731 sched/fair: Fix cfs_rq_clock_pelt() for throttled cfs_rq
Since commit 2312729688 ("sched/fair: Update scale invariance of PELT")
change to use rq_clock_pelt() instead of rq_clock_task(), we should also
use rq_clock_pelt() for throttled_clock_task_time and throttled_clock_task
accounting to get correct cfs_rq_clock_pelt() of throttled cfs_rq. And
rename throttled_clock_task(_time) to be clock_pelt rather than clock_task.

Fixes: 2312729688 ("sched/fair: Update scale invariance of PELT")
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20220408115309.81603-1-zhouchengming@bytedance.com
2022-04-22 12:14:07 +02:00
zgpeng 0635490078 sched/fair: Move calculate of avg_load to a better location
In calculate_imbalance function, when the value of local->avg_load is
greater than or equal to busiest->avg_load, the calculated sds->avg_load is
not used. So this calculation can be placed in a more appropriate position.

Signed-off-by: zgpeng <zgpeng@tencent.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Samuel Liao <samuelliao@tencent.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/1649239025-10010-1-git-send-email-zgpeng@tencent.com
2022-04-22 12:14:07 +02:00
Hailong Liu 915a087e4c psi: Fix trigger being fired unexpectedly at initial
When a trigger being created, its win.start_value and win.start_time are
reset to zero. If group->total[PSI_POLL][t->state] has accumulated before,
this trigger will be fired unexpectedly in the next period, even if its
growth time does not reach its threshold.

So set the window of the new trigger to the current state value.

Signed-off-by: Hailong Liu <liuhailong@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Link: https://lore.kernel.org/r/1648789811-3788971-1-git-send-email-liuhailong@linux.alibaba.com
2022-04-22 12:14:06 +02:00
Marco Elver 78ed93d72d signal: Deliver SIGTRAP on perf event asynchronously if blocked
With SIGTRAP on perf events, we have encountered termination of
processes due to user space attempting to block delivery of SIGTRAP.
Consider this case:

    <set up SIGTRAP on a perf event>
    ...
    sigset_t s;
    sigemptyset(&s);
    sigaddset(&s, SIGTRAP | <and others>);
    sigprocmask(SIG_BLOCK, &s, ...);
    ...
    <perf event triggers>

When the perf event triggers, while SIGTRAP is blocked, force_sig_perf()
will force the signal, but revert back to the default handler, thus
terminating the task.

This makes sense for error conditions, but not so much for explicitly
requested monitoring. However, the expectation is still that signals
generated by perf events are synchronous, which will no longer be the
case if the signal is blocked and delivered later.

To give user space the ability to clearly distinguish synchronous from
asynchronous signals, introduce siginfo_t::si_perf_flags and
TRAP_PERF_FLAG_ASYNC (opted for flags in case more binary information is
required in future).

The resolution to the problem is then to (a) no longer force the signal
(avoiding the terminations), but (b) tell user space via si_perf_flags
if the signal was synchronous or not, so that such signals can be
handled differently (e.g. let user space decide to ignore or consider
the data imprecise).

The alternative of making the kernel ignore SIGTRAP on perf events if
the signal is blocked may work for some usecases, but likely causes
issues in others that then have to revert back to interception of
sigprocmask() (which we want to avoid). [ A concrete example: when using
breakpoint perf events to track data-flow, in a region of code where
signals are blocked, data-flow can no longer be tracked accurately.
When a relevant asynchronous signal is received after unblocking the
signal, the data-flow tracking logic needs to know its state is
imprecise. ]

Fixes: 97ba62b278 ("perf: Add support for SIGTRAP on perf events")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/r/20220404111204.935357-1-elver@google.com
2022-04-22 12:14:05 +02:00