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| author | Peter Zijlstra <peterz@infradead.org> | 2017-03-22 11:35:49 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-03-23 19:10:06 +0100 |
| commit | 1b367ece0d7e696cab1c8501bab282cc6a538b3f (patch) | |
| tree | ccbcb4ec20dc4570912352533738458a75b73ff2 /kernel/futex.c | |
| parent | 499f5aca2cdd5e958b27e2655e7e7f82524f46b1 (diff) | |
| download | linux-1b367ece0d7e696cab1c8501bab282cc6a538b3f.tar.gz | |
futex: Use smp_store_release() in mark_wake_futex()
Since the futex_q can dissapear the instruction after assigning NULL, this really should be a RELEASE barrier. That stops loads from hitting dead memory too. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: juri.lelli@arm.com Cc: bigeasy@linutronix.de Cc: xlpang@redhat.com Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: jdesfossez@efficios.com Cc: dvhart@infradead.org Cc: bristot@redhat.com Link: http://lkml.kernel.org/r/20170322104151.604296452@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/futex.c')
| -rw-r--r-- | kernel/futex.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 1531cc405270..cc1034038285 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1290,8 +1290,7 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q) * memory barrier is required here to prevent the following * store to lock_ptr from getting ahead of the plist_del. */ - smp_wmb(); - q->lock_ptr = NULL; + smp_store_release(&q->lock_ptr, NULL); } static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_q *top_waiter, |