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-rw-r--r--kernel/sched/core.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 32ba789c544c..bbf8b32fc69e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -432,10 +432,11 @@ void wake_q_add(struct wake_q_head *head, struct task_struct *task)
* its already queued (either by us or someone else) and will get the
* wakeup due to that.
*
- * This cmpxchg() implies a full barrier, which pairs with the write
- * barrier implied by the wakeup in wake_up_q().
+ * In order to ensure that a pending wakeup will observe our pending
+ * state, even in the failed case, an explicit smp_mb() must be used.
*/
- if (cmpxchg(&node->next, NULL, WAKE_Q_TAIL))
+ smp_mb__before_atomic();
+ if (cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL))
return;
get_task_struct(task);