diff options
Diffstat (limited to 'kernel/futex.c')
| -rw-r--r-- | kernel/futex.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 3057dabf726f..fc68462801de 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1939,8 +1939,12 @@ static int unqueue_me(struct futex_q *q) /* In the common case we don't take the spinlock, which is nice. */ retry: - lock_ptr = q->lock_ptr; - barrier(); + /* + * q->lock_ptr can change between this read and the following spin_lock. + * Use READ_ONCE to forbid the compiler from reloading q->lock_ptr and + * optimizing lock_ptr out of the logic below. + */ + lock_ptr = READ_ONCE(q->lock_ptr); if (lock_ptr != NULL) { spin_lock(lock_ptr); /* |