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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-11-07 16:01:00 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-11-16 12:29:04 +0300 |
| commit | f285144f81e814f39342dbf5321d6ba939890b1b (patch) | |
| tree | d9194b57593b5767efab27870bfda51e730b4798 /security/selinux/netnode.c | |
| parent | 527b0a76f41d062381adbb55c8eb61e32cb0bfc9 (diff) | |
| download | linux-f285144f81e814f39342dbf5321d6ba939890b1b.tar.xz | |
sched/x86: Do not clear PREEMPT_NEED_RESCHED on preempt count reset
The per-cpu preempt count of x86 contains two values, the actual preempt
count and the inverted PREEMPT_NEED_RESCHED bit. If a corrupted preempt
count is detected the preempt_count_set() function is used to reset the
preempt count.
In case the inverted PREEMPT_NEED_RESCHED bit is zero at the time of the
reset, the preemption indication is lost. Use raw_cpu_cmpxchg_4() to reset
only the count part and leave the PREEMPT_NEED_RESCHED bit as it is.
This improves the kernel's behavior when it runs into preempt count leaks
and tries to fix them up.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1478523660-733-1-git-send-email-schwidefsky@de.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'security/selinux/netnode.c')
0 files changed, 0 insertions, 0 deletions