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Commit 87ed28db authored by Jens Axboe's avatar Jens Axboe Committed by Treehugger Robot
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UPSTREAM: io_uring: don't drop completion lock before timer is fully initialized 



No upstream commit exists for this patch.

If we drop the lock right after adding it to the timeout list, then
someone attempting to kill timeouts will find it in an indeterminate
state. That means that cancelation could attempt to cancel and remove
a timeout, and then io_timeout() proceeds to init and add the timer
afterwards.

Ensure the timeout request is fully setup before we drop the
completion lock, which guards cancelation as well.

Bug: 278721720
Reported-and-tested-by: default avatarLee Jones <lee@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 6de3014d)
Signed-off-by: default avatarLee Jones <joneslee@google.com>
Change-Id: I6247b62e07825a0f06c7997d767dfc26fc4126e3
parent ce6a504d

fs/io_uring.c

+1 −1
Original line number Diff line number Diff line
@@ -2076,12 +2076,12 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	req->sequence -= span;

add:

	list_add(&req->list, entry);

	spin_unlock_irq(&ctx->completion_lock);



	hrtimer_init(&req->timeout.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	req->timeout.timer.function = io_timeout_fn;

	hrtimer_start(&req->timeout.timer, timespec64_to_ktime(ts),

			HRTIMER_MODE_REL);

	spin_unlock_irq(&ctx->completion_lock);

	return 0;

}