From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793209742; b=O0elseDC7MazSmgiVs9WdEzpkFS4D94qR7a8utQYhc8JMC62idGPAESTs/YOMSPAsLO7 6T9jvXsP0nwWmorIB/b/187KjwallI/2sQwkwpuRfJeuAFriuqyb3JwmZoiYAs1xp+HkF cWm4jBB/56Tn83iKfHf2CxT17kv5fv926vShGPEb+Mw7qMe75Twka7KZ4ybXgBq4xirVN w+m6hrCCrRAxI2mWrOCBVZvUywwTrI5UnK/69BAheUMonb5x+J6OHgCKsA8S27gi5efZj /WOxUwPrk+F3700hDRq/VhuOD9thLSgsMH0/CbuzZ/FMt8QEpgAXHHh5POk8dg1b8uw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209742; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=gLB58zLceCs+tMOAjaQmm2315k0VWV3fjacjNSeIBcE=; b=qYJ+gv0K017UM+nWUvELK3eGmBZVhoqK71tZlDpHHpWvXZwhoeOhPH4Dj3+6bNp/Ze6+ 2ee8cVk+mDcwSa7FJh5PPVnbbYx+feohdrw+vP0JJH6+ad8TzyGmp4Ru6cn3W7xfJyTKp nCa4qS7GtRkWIsTaExBUgwFmrLrA8Ig4iOjDgyaLlOZ2lYuI6L42WHA0brlF6Tfoboo2o 1O0HRJOfyCml4nAwSPyY5BaYzMi8+4rKDhRGMFTtWm6y/pdGR2CQNOiI1NHmkgF5MKXYa XJGYdbippO+7ZadfMNyPmjlQLgXJZRYkUR3YjcN4PHVr6V3YhjdiA7wyDVPlgDedeNQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="sBeA8jN/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B46D606A31A; Wed, 28 Oct 2026 17:49:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=sBeA8jN/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD82F1F01825; Wed, 28 Oct 2026 17:49:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793209742; bh=gLB58zLceCs+tMOAjaQmm2315k0VWV3fjacjNSeIBcE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=sBeA8jN/mvzKANXRcIpG6nMnoL4FJHfGrVTteTHTunccS3AUD3YiTUKSLjPP2KlOq s+8Hror4/fX43TEOli0kN80qnJq+BwhiF1zQfO6aEo24jPfIHLWvpRjnYG/JxS+kYR BtOdRjtRCVQzPLcGPniv29ilEv6BQvUhM+alEDQo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josef Bacik , Jens Axboe Subject: [PATCH 6.18 061/109] io_uring/poll: drop stale double poll entry on rearm Date: Wed, 28 Oct 2026 18:00:45 +0100 Message-ID: <20261028165943.795217100@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165942.357251485@linuxfoundation.org> References: <20261028165942.357251485@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik Commit f2dbe87968a3aef74a11c025776d293b80964d3f upstream. A file that uses two wait queues for poll, e.g. a tty, gets a second io_poll entry, which IORING_OP_POLL_ADD keeps in ->async_data until the request is freed. io_poll_add() can run more than once for a request though: IORING_OP_POLL_REMOVE with one of the update flags disarms and rearms it, and io_poll_task_func() reissues it if a wake up turns out to be spurious. The second poll_wait() of the new round then finds *poll_ptr set, with ->head cleared by the disarm, and __io_queue_proc() fails what it takes for a third wait queue with -EINVAL. For an update that means that the poll request is completed with -ECANCELED, while the update itself reports success. For a spurious wake up, e.g. tcsetattr() on the polled tty, the poll request fails with -EINVAL. Free the old entry and clear the poll flags before arming, which is what io_arm_apoll() does for internal polling. All entries have been removed from their wait queues at that point. Fixes: b69de288e913 ("io_uring: allow events and user_data update of running poll requests") Fixes: 6e5aedb9324a ("io_uring/poll: attempt request issue after racy poll wakeup") Assisted-by: LLM Signed-off-by: Josef Bacik Link: https://patch.msgid.link/20261015-b4-io-uring-fixes-v1-21-c1556f5d7bf5@toxicpanda.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/poll.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -915,6 +915,15 @@ int io_poll_add(struct io_kiocb *req, un ipt.pt._qproc = io_poll_queue_proc; + /* + * A poll update or a spurious wake up arms the request again. Forget + * the entries of the previous round like io_arm_apoll() does, a stale + * second entry would be taken for a third wait queue. + */ + if (req_has_async_data(req)) + io_req_async_data_free(req); + req->flags &= ~(REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL); + ret = __io_arm_poll_handler(req, poll, &ipt, poll->events, issue_flags); if (ret > 0) { io_req_set_res(req, ipt.result_mask, 0);