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authorAlex Shi <alex.shi@linaro.org>2014-01-10 10:50:57 +0800
committerAlex Shi <alex.shi@linaro.org>2014-01-10 10:50:57 +0800
commit450cdfa9c5713551ab1438ab210679868b52a994 (patch)
treeedd98f9698aa88af55a3a1ee3de62e52917c39ba /kernel/sched/core.c
parentbf78886fb6c4131885f84f3eaaf7474509d40e51 (diff)
parent8b4ed85b8404ffe7e10ee410c4df3968b86f0793 (diff)
downloadlinaro-lsk-450cdfa9c5713551ab1438ab210679868b52a994.tar.gz
Merge remote-tracking branch 'stable/linux-3.10.y' into linux-linaro-lsk
Conflicts: arch/arm64/kernel/smp.c Signed-off-by: Alex Shi <alex.shi@linaro.org>
Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r--kernel/sched/core.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fb9b7b74a83..fc5112c20fe 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1487,7 +1487,13 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
unsigned long flags;
int cpu, success = 0;
- smp_wmb();
+ /*
+ * If we are going to wake up a thread waiting for CONDITION we
+ * need to ensure that CONDITION=1 done by the caller can not be
+ * reordered with p->state check below. This pairs with mb() in
+ * set_current_state() the waiting thread does.
+ */
+ smp_mb__before_spinlock();
raw_spin_lock_irqsave(&p->pi_lock, flags);
if (!(p->state & state))
goto out;
@@ -2980,6 +2986,12 @@ need_resched:
if (sched_feat(HRTICK))
hrtick_clear(rq);
+ /*
+ * Make sure that signal_pending_state()->signal_pending() below
+ * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
+ * done by the caller to avoid the race with signal_wake_up().
+ */
+ smp_mb__before_spinlock();
raw_spin_lock_irq(&rq->lock);
switch_count = &prev->nivcsw;