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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-01-27 11:52:50 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-01-27 11:52:50 -0800 |
| commit | 9881051828375a872964f91bf985b8a35e4fbaef (patch) | |
| tree | a7e8a0503ecdb19bdcd5cf2bf5696143f2c4900b /kernel/futex.c | |
| parent | 0d484375d73ad2ec39a395365449a70c200645b1 (diff) | |
| parent | e158488be27b157802753a59b336142dc0eb0380 (diff) | |
| download | linux-9881051828375a872964f91bf985b8a35e4fbaef.tar.bz2 | |
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner:
"A small series of fixes which all address possible missed wakeups:
- Document and fix the wakeup ordering of wake_q
- Add the missing barrier in rcuwait_wake_up(), which was documented
in the comment but missing in the code
- Fix the possible missed wakeups in the rwsem and futex code"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rwsem: Fix (possible) missed wakeup
futex: Fix (possible) missed wakeup
sched/wake_q: Fix wakeup ordering for wake_q
sched/wake_q: Document wake_q_add()
sched/wait: Fix rcuwait_wake_up() ordering
Diffstat (limited to 'kernel/futex.c')
| -rw-r--r-- | kernel/futex.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index be3bff2315ff..fdd312da0992 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1452,11 +1452,7 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q) if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex\n")) return; - /* - * Queue the task for later wakeup for after we've released - * the hb->lock. wake_q_add() grabs reference to p. - */ - wake_q_add(wake_q, p); + get_task_struct(p); __unqueue_futex(q); /* * The waiting task can free the futex_q as soon as q->lock_ptr = NULL @@ -1466,6 +1462,13 @@ static void mark_wake_futex(struct wake_q_head *wake_q, struct futex_q *q) * plist_del in __unqueue_futex(). */ smp_store_release(&q->lock_ptr, NULL); + + /* + * Queue the task for later wakeup for after we've released + * the hb->lock. wake_q_add() grabs reference to p. + */ + wake_q_add(wake_q, p); + put_task_struct(p); } /* |