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| author | Tejun Heo <tj@kernel.org> | 2009-11-13 18:33:53 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-11-15 09:59:54 +0100 |
| commit | 498657a478c60be092208422fefa9c7b248729c2 (patch) | |
| tree | c04542330fbbfaaa863fbec0f565b79c89df7033 /kernel | |
| parent | 055a00865dcfc8e61f3cbefbb879c9577bd36ae5 (diff) | |
| download | blackbird-op-linux-498657a478c60be092208422fefa9c7b248729c2.tar.gz blackbird-op-linux-498657a478c60be092208422fefa9c7b248729c2.zip | |
sched, kvm: Fix race condition involving sched_in_preempt_notifers
In finish_task_switch(), fire_sched_in_preempt_notifiers() is
called after finish_lock_switch().
However, depending on architecture, preemption can be enabled after
finish_lock_switch() which breaks the semantics of preempt
notifiers.
So move it before finish_arch_switch(). This also makes the in-
notifiers symmetric to out- notifiers in terms of locking - now
both are called under rq lock.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Avi Kivity <avi@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4AFD2801.7020900@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 701eca4958a2..cea2beac7909 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2758,9 +2758,9 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev) prev_state = prev->state; finish_arch_switch(prev); perf_event_task_sched_in(current, cpu_of(rq)); + fire_sched_in_preempt_notifiers(current); finish_lock_switch(rq, prev); - fire_sched_in_preempt_notifiers(current); if (mm) mmdrop(mm); if (unlikely(prev_state == TASK_DEAD)) { |
