github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-12 16:18:45 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

Fix lockup in requeue-PI during signal/timeout wakeups,

Browse Source 
by Sebastian Andrzej Siewior.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAmn2/AYRHG1pbmdvQGtl
 cm5lbC5vcmcACgkQEnMQ0APhK1iQCA//cAsib3cTZr9GAvjX5+Fjf3Dsl4HdO7qr
 XzOeMNtvnz0wcWgNCq02vwutbQwzRRr71DqDzhYV7YGxwyrqw+fE0RMvQDEML3I6
 SI1I8aj1Eo+WNHcy7HajYd0WBiOuMAcSZsa+3kYWKnDZ0GJadbQHTrQo5nT8VgFf
 o+aGU4kivGsKlz+UrcTxViNovenQ3mysuY8Pn3xKFlwn+vnJIwT2WUuQ1U8wK2OY
 edH9O4UEJkPFIOxqhL5+s4J/utsFasEFSLMpx9NpYzOGH85PTxIJg6O+n9a5NTAa
 40tsXlWkDsi/AfiNbWBYOpw8gS2yHyrLuY9CLBuxiRojfS6TePzfJyCPFvLLhBau
 90y02GskoDe4DFox9f+33BykR48yWxGOtxXiFJ1caXH4HsZi5z6Wd3vFCQp61zwm
 RPGKA5k8a9+hlToOpaAwHqA8ODbnEyRKwhG/OdnHo7cKPAWH+2awSSyW30DQoo+o
 mBYcMNbNeZObzQ/DErZvErDpq0hePATn/zfMFNEtXh+0Y1WZWix0NT5atHbtid+w
 0tRaazUpNCpGNp+7xxFGmaHxN/bPCmjZXpTIWIhc6vn8DNx/Y059g3ItYyeiRVkZ
 WD0vWdBgYerK0CfYsllh5d4fiTSLKoILq/f5Zc5Pq/GnVAZe/JQy7v6Duj+HmJ9O
 g9es4fSjzBs=
 =HUBJ
 -----END PGP SIGNATURE-----

Merge tag 'locking-urgent-2026-05-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fix from Ingo Molnar:
 "Fix lockup in requeue-PI during signal/timeout wakeups, by Sebastian
  Andrzej Siewior"

* tag 'locking-urgent-2026-05-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Prevent lockup in requeue-PI during signal/ timeout wakeup
This commit is contained in:
Linus Torvalds 2026-05-03 08:17:09 -07:00
commit cffcf520fd
1 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
kernel/futex/requeue.c
View File

@ -319,8 +319,11 @@ futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1,
return -EINVAL;
/* Ensure that this does not race against an early wakeup */
if (!futex_requeue_pi_prepare(top_waiter, NULL))
if (!futex_requeue_pi_prepare(top_waiter, NULL)) {
plist_del(&top_waiter->list, &hb1->chain);
futex_hb_waiters_dec(hb1);
return -EAGAIN;
}
/*
* Try to take the lock for top_waiter and set the FUTEX_WAITERS bit
@ -722,10 +725,12 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb,
/*
* We were woken prior to requeue by a timeout or a signal.
* Unqueue the futex_q and determine which it was.
* Conditionally unqueue the futex_q and determine which it was.
*/
plist_del(&q->list, &hb->chain);
futex_hb_waiters_dec(hb);
if (!plist_node_empty(&q->list)) {
plist_del(&q->list, &hb->chain);
futex_hb_waiters_dec(hb);
}
/* Handle spurious wakeups gracefully */
ret = -EWOULDBLOCK;