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sched/core: Fix preempt warning in ttwu

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John reported a DEBUG_PREEMPT warning caused by commit:

  aacedf26fb76 ("sched/core: Optimize try_to_wake_up() for local wakeups")

I overlooked that ttwu_stat() requires preemption disabled.

Reported-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: aacedf26fb76 ("sched/core: Optimize try_to_wake_up() for local wakeups")
Link: https://lkml.kernel.org/r/20190710105736.GK3402@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Change-Id: I385c5e0796c36e35761cc4658edd3c00ac908bfb
Signed-off-by: Alexander Winkowski <dereference23@outlook.com>
This commit is contained in:
Peter Zijlstra
2019-07-10 12:57:36 +02:00
committed by nisel
parent a8736dd057
commit ee8d7807c7
1 changed files with 3 additions and 1 deletions
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4
kernel/sched/core.c
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@@ -2893,6 +2893,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags,
unsigned long flags;
int cpu, success = 0;
preempt_disable();
if (p == current) {
/*
* We're waking current, this means 'p->on_rq' and 'task_cpu(p)
@@ -2906,7 +2907,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags,
* it disabling IRQs (this allows not taking ->pi_lock).
*/
if (!(p->state & state))
return false;
goto out;
success = 1;
cpu = task_cpu(p);
@@ -3021,6 +3022,7 @@ unlock:
out:
if (success)
ttwu_stat(p, cpu, wake_flags);
preempt_enable();
return success;
}