From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 011B23559C4; Tue, 6 Jan 2026 17:29:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767720585; cv=none; b=eIuTcxQZRuP2Un7Y+FO4YRv2Zv4NRtb38X2wflBaggb99Xe6NsIv5Z2TlSrxyLAHn7ZbrlgKWBdOZHEG1SiDdQTSTG0bTcuf0k8r/b173/Epv2//UDRMSo9zgd+n/57igmLF36vA12ACUfj0FvaQ6cKJCIyLAqyquknQaP7+3MA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767720585; c=relaxed/simple; bh=BuvwAA0T77KmQe3hb+BphT5HkREvCxelp+59VmPilKA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZCQDxjhgXQasKZzvo6i4T8C4P++r1vuwpsUdzRi1H5i+HB2qLb6jM4KYIs2MciaOZsyKMAgeuKHUipvA96o8Kku65xHXosnH2MhnSBy7/u6MyWUi726Q0JYGW9h8fMuHTo/cVYwDtr7VXLzTW3z3/xb9xVoPOBiT3PXXuP1eE1U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=XaRrQkcQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="XaRrQkcQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A6F1C116C6; Tue, 6 Jan 2026 17:29:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767720584; bh=BuvwAA0T77KmQe3hb+BphT5HkREvCxelp+59VmPilKA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XaRrQkcQfgFa46TJrQhMqwYykxYc/57VoDX1qHtPkYcLcwBHdX6xFAg6nLwdXd1my Vb+Kg7Wm3A7SoST6rkHNKtcAcI+GZeJTbF4ArfJPBeZIaA+cxvDRO3KmNh40CyiQCC dmRri7cXFd81pn7BwcEKq5MuVLDHGeZpY2f1LxE0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com, Jens Axboe Subject: [PATCH 6.12 249/567] io_uring/poll: correctly handle io_poll_add() return value on update Date: Tue, 6 Jan 2026 18:00:31 +0100 Message-ID: <20260106170500.526604146@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260106170451.332875001@linuxfoundation.org> References: <20260106170451.332875001@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jens Axboe Commit 84230ad2d2afbf0c44c32967e525c0ad92e26b4e upstream. When the core of io_uring was updated to handle completions consistently and with fixed return codes, the POLL_REMOVE opcode with updates got slightly broken. If a POLL_ADD is pending and then POLL_REMOVE is used to update the events of that request, if that update causes the POLL_ADD to now trigger, then that completion is lost and a CQE is never posted. Additionally, ensure that if an update does cause an existing POLL_ADD to complete, that the completion value isn't always overwritten with -ECANCELED. For that case, whatever io_poll_add() set the value to should just be retained. Cc: stable@vger.kernel.org Fixes: 97b388d70b53 ("io_uring: handle completions in the core") Reported-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com Tested-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/poll.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -1038,12 +1038,17 @@ found: ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED); /* successfully updated, don't complete poll request */ - if (!ret2 || ret2 == -EIOCBQUEUED) + if (ret2 == IOU_ISSUE_SKIP_COMPLETE) goto out; + /* request completed as part of the update, complete it */ + else if (ret2 == IOU_OK) + goto complete; } - req_set_fail(preq); io_req_set_res(preq, -ECANCELED, 0); +complete: + if (preq->cqe.res < 0) + req_set_fail(preq); preq->io_task_work.func = io_req_task_complete; io_req_task_work_add(preq); out: