From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19D5AC43144 for ; Mon, 25 Jun 2018 06:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C84D5254AE for ; Mon, 25 Jun 2018 06:20:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="CoNVYGWo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C84D5254AE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752347AbeFYGUh (ORCPT ); Mon, 25 Jun 2018 02:20:37 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:49174 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752309AbeFYGUf (ORCPT ); Mon, 25 Jun 2018 02:20:35 -0400 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w5P6JWLo182358; Mon, 25 Jun 2018 06:20:33 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2017-10-26; bh=4ZcfKmmXrDfkvdjACbGYSZDpwhO9LBoVbRMvnT/tifU=; b=CoNVYGWo0FKbNM0qV1jtb8SNHccltOrX8Y7ZHmAp5ZlIkaDlHyuErXXb1yzH/YXaTrLK rnK2biUNzLIYsO527y647Mx8acAD/uPx193oo7L6fpScJWoSKf1HOpX4fL3K5nBX6syY gGIhkIYqZIhXUJpJVdHQTGJnEvpLuAP8Pq2srM4urqutbOpmq+fE/GEr3/biO6GkZNh2 YPFTBg/DNTS9vp+XkgtJfGi5gDVc026pSA51uRM7QIEHmGeuO5vOaJah/3vic0A1oasz mDfzoRDdR8mksZoq929YMyR1BW5TUUZUJRHIHUtY25Cw6ZkpfB5JuT6GPLk8xUNtx4P6 fg== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2130.oracle.com with ESMTP id 2jt7nasatk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 25 Jun 2018 06:20:33 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w5P6KWEA029925 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 25 Jun 2018 06:20:32 GMT Received: from abhmp0012.oracle.com (abhmp0012.oracle.com [141.146.116.18]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w5P6KWRF004825; Mon, 25 Jun 2018 06:20:32 GMT Received: from will-ThinkCentre-M910s.cn.oracle.com (/10.182.70.254) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 24 Jun 2018 23:20:31 -0700 From: Jianchao Wang To: axboe@kernel.dk Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] blk-mq-fs: invoke queue_for_each_hw_ctx under sysfs_lock Date: Mon, 25 Jun 2018 14:21:39 +0800 Message-Id: <1529907699-2054-1-git-send-email-jianchao.w.wang@oracle.com> X-Mailer: git-send-email 2.7.4 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8934 signatures=668703 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1806250075 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org blk_mq_run_hw_queues and blk_mq_start_stopped_hw_queues in queue_state_write will invoke queue_for_each_hw_ctx. It will race with blk_mq_realloc_hw_ctxs and incur NULL pointer reference. Put them under sysfs_lock to serialize the accessing to queue_hw_ctx and nr_hw_queues. Signed-off-by: Jianchao Wang --- block/blk-mq-debugfs.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index ffa6223..2e0c444 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -151,6 +151,7 @@ static ssize_t queue_state_write(void *data, const char __user *buf, { struct request_queue *q = data; char opbuf[16] = { }, *op; + int res; /* * The "state" attribute is removed after blk_cleanup_queue() has called @@ -169,9 +170,17 @@ static ssize_t queue_state_write(void *data, const char __user *buf, return -EFAULT; op = strstrip(opbuf); if (strcmp(op, "run") == 0) { + res = mutex_lock_interruptible(&q->sysfs_lock); + if (res) + goto out; blk_mq_run_hw_queues(q, true); + mutex_unlock(&q->sysfs_lock); } else if (strcmp(op, "start") == 0) { + res = mutex_lock_interruptible(&q->sysfs_lock); + if (res) + goto out; blk_mq_start_stopped_hw_queues(q, true); + mutex_unlock(&q->sysfs_lock); } else if (strcmp(op, "kick") == 0) { blk_mq_kick_requeue_list(q); } else { @@ -180,6 +189,7 @@ static ssize_t queue_state_write(void *data, const char __user *buf, pr_err("%s: use 'run', 'start' or 'kick'\n", __func__); return -EINVAL; } +out: return count; } -- 2.7.4