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 440B21E515; Fri, 9 Jan 2026 12:41:13 +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=1767962474; cv=none; b=W15KbPf0a15TYQmk55Is+UZGIs0GXYi60Zy3/hb4KYrHSq32wgryxPz1DVot16D/jlYYDAubni5xbmmgxVA31E/8b45eoWIXEEodWZdKe+pSu/d90wnM7147zRSGYI5+4Pclo2wce3ykEkufQy5+Jwh4EYcf441aaIB2+j2GGsM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767962474; c=relaxed/simple; bh=Xuh+uYalqI8mV8T6vcO9rEkqwrIgMwJKBeTSH6bWSmc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UwPRDnFDZsCLhx73kpE6A+MX+6VoDhHuer7198TzRYcGafdweZAcKEibACwrcbmPwLLmFLbuUNXzUUdmHt8n3swktXpc8r5TeTUBwx7yMMLDPgLom7CnICOi4jgBDt6oEuYTWtnTjMKpKLb7pvSfXuCUGbFQmarnL2mw9WfizrU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mR02Md+O; 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="mR02Md+O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 47887C19423; Fri, 9 Jan 2026 12:41:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767962473; bh=Xuh+uYalqI8mV8T6vcO9rEkqwrIgMwJKBeTSH6bWSmc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mR02Md+O62RHawdYwD1/PFuqeP1V+F7LVVi0xZRgq4Eodup3JEzijzurp4nVndweC ISU6K4kU8Yd5cdyaTSp3QYH2kRpw+Q4Kft1I4cNIUOJO0XxYYkXPmhNbfuK2a7lWnh HN5Qcar+Y0pkDKY5bvZkYt8UKHQMBCJdnDgJMft8= 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 6.1 376/634] io_uring/poll: correctly handle io_poll_add() return value on update Date: Fri, 9 Jan 2026 12:40:54 +0100 Message-ID: <20260109112131.679351598@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112117.407257400@linuxfoundation.org> References: <20260109112117.407257400@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 6.1-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); io_req_task_complete(preq, &locked); out: io_ring_submit_unlock(ctx, issue_flags);