diff options
| -rw-r--r-- | kernel/futex.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 5872e3507f35..5e71a6bf6f6b 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -270,7 +270,13 @@ static void wake_futex(struct futex_q *q) /* * The waiting task can free the futex_q as soon as this is written, * without taking any locks. This must come last. + * + * A memory barrier is required here to prevent the following store + * to lock_ptr from getting ahead of the wakeup. Clearing the lock + * at the end of wake_up_all() does not prevent this store from + * moving. */ + wmb(); q->lock_ptr = NULL; } |