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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pavel Begunkov <asml.silence@gmail.com>,
        Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0360/1039] io_uring: remove double poll on poll update
Date:   Mon, 24 Jan 2022 19:35:49 +0100
Message-Id: <20220124184137.379491661@linuxfoundation.org>
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From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit e840b4baf3cfb37e2ead4f649a45bb78178677ff ]

Before updating a poll request we should remove it from poll queues,
including the double poll entry.

Fixes: b69de288e913 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ac39e7f80152613603b8a6cc29a2b6063ac2434f.1639605189.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/io_uring.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index fb2a0cb4aaf83..72496f424c155 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5928,6 +5928,7 @@ static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags)
 	 * update those. For multishot, if we're racing with completion, just
 	 * let completion re-add it.
 	 */
+	io_poll_remove_double(preq);
 	completing = !__io_poll_remove_one(preq, &preq->poll, false);
 	if (completing && (preq->poll.events & EPOLLONESHOT)) {
 		ret = -EALREADY;
-- 
2.34.1