Commit 498657a4 authored by Tejun Heo's avatar Tejun Heo Committed by Ingo Molnar
Browse files

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

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: default avatarTejun Heo <>
Acked-by: default avatarAvi Kivity <>
Cc: Peter Zijlstra <>
LKML-Reference: <>
Signed-off-by: default avatarIngo Molnar <>
parent 055a0086
...@@ -2758,9 +2758,9 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev) ...@@ -2758,9 +2758,9 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
prev_state = prev->state; prev_state = prev->state;
finish_arch_switch(prev); finish_arch_switch(prev);
perf_event_task_sched_in(current, cpu_of(rq)); perf_event_task_sched_in(current, cpu_of(rq));
finish_lock_switch(rq, prev); finish_lock_switch(rq, prev);
if (mm) if (mm)
mmdrop(mm); mmdrop(mm);
if (unlikely(prev_state == TASK_DEAD)) { if (unlikely(prev_state == TASK_DEAD)) {
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