io_uring/wait: fix min_timeout behavior

The wakeup condition if a min timeout is present and has expired is that
at least _one_ CQE was posted. Thus set the cq_tail target to
->cq_min_tail + 1. Without this commit a spurious wakeup can result in a
premature wakeup because io_should_wake() will return true even if _no_
CQE was posted at all.

Cc: Tip ten Brink <tip@tenbrinkmeijs.com>
Fixes: e15cb2200b ("io_uring: fix min_wait wakeups for SQPOLL")
Cc: stable@vger.kernel.org
Signed-off-by: Christian A. Ehrhardt <lk@c--e.de>
Link: https://patch.msgid.link/20260606201120.1441447-1-lk@c--e.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christian A. Ehrhardt 2026-06-06 22:11:20 +02:00 committed by Jens Axboe
commit 29fe1bd01b

View file

@ -103,7 +103,7 @@ static enum hrtimer_restart io_cqring_min_timer_wakeup(struct hrtimer *timer)
}
/* any generated CQE posted past this time should wake us up */
iowq->cq_tail = iowq->cq_min_tail;
iowq->cq_tail = iowq->cq_min_tail + 1;
hrtimer_update_function(&iowq->t, io_cqring_timer_wakeup);
hrtimer_set_expires(timer, iowq->timeout);