Commit 539bcb57 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: fix tw losing poll events 



We may never try to process a poll wake and its mask if there was
multiple wake ups racing for queueing up a tw. Force
io_poll_check_events() to update the mask by vfs_poll().

Cc: stable@vger.kernel.org
Fixes: aa43477b ("io_uring: poll rework")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/00344d60f8b18907171178d7cf598de71d127b0b.1668710222.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b98186ae

io_uring/poll.c

+7 −0
Original line number Diff line number Diff line
@@ -228,6 +228,13 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked) 
			return IOU_POLL_DONE;

		if (v & IO_POLL_CANCEL_FLAG)

			return -ECANCELED;

		/*

		 * cqe.res contains only events of the first wake up

		 * and all others are be lost. Redo vfs_poll() to get

		 * up to date state.

		 */

		if ((v & IO_POLL_REF_MASK) != 1)

			req->cqe.res = 0;



		/* the mask was stashed in __io_poll_execute */

		if (!req->cqe.res) {