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,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 00AC3C43144 for ; Fri, 22 Jun 2018 07:10:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE69323E0D for ; Fri, 22 Jun 2018 07:10:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="hJwiYr08" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE69323E0D 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 S1751329AbeFVHKf (ORCPT ); Fri, 22 Jun 2018 03:10:35 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:56476 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750934AbeFVHKa (ORCPT ); Fri, 22 Jun 2018 03:10:30 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w5M79PQd049572; Fri, 22 Jun 2018 07:10:28 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=8t9N+GooV91tX9yP5yUigIabP9g7G/kXNZ2LeuGc4R4=; b=hJwiYr08sUCJJ39t/Znu9VAwSp8M1w9gdUl0Lpt674IMAsFa8/g13Y7mcK09GSA/U1QV F3qSIMn4j+rk3supfPMp69984lL2bvcPoI8oyWIsW3mwtSrGaGs+iz09YGbMB9LPpQYD h8ZD5rwgfCy1Niziz2mwhJp/AFboo1mA4NikiYeemZwT1hbNxGQno0J4KMl4xfgwKYil y5yz4YnVKiDvchsMG+d2Y1Utbl5Trc4Bx0C8ErFjXpDbcZpD2ViNMwGBEysVtxTQAXDu PCy2NzMHqrOhhMwJp2Ho8RElsVNwEZH7CeUjhLqcmrOqU/dsZauv1vQX63xpdcJlHqA7 Rw== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp2120.oracle.com with ESMTP id 2jrp8hrrn8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 22 Jun 2018 07:10:28 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w5M7ARLb008693 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 22 Jun 2018 07:10:27 GMT Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w5M7AQcq011501; Fri, 22 Jun 2018 07:10:27 GMT Received: from will-ThinkCentre-M910s.cn.oracle.com (/10.182.70.254) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 22 Jun 2018 00:10:26 -0700 From: Jianchao Wang To: axboe@kernel.dk Cc: bart.vanassche@wdc.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/3] block: fix the lock inversion caused by kobject_del under sysfs_lock Date: Fri, 22 Jun 2018 15:11:17 +0800 Message-Id: <1529651480-1734-1-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=8931 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=648 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1806220081 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jens Currently, the kobject_del for sysfs mq and hctx entry is invoked under q->sysfs_lock. lock inversion will came up when someone try to access the sysfs entries concurrently. The scenario is as below: hold q->sysfs_lock access mq,hctx sysfs entries kobject_del __kernfs_remove kernfs_get_active kernfs_drain wait kn->active require q->sysfs_lock To avoid this issue, kobject_del for mq and hctx sysfs entries mustn't be inovked under sysfs_lock. These patch set is to achieve this. 1st patch introduces blk_queue_registered to test QUEUE_FLAG_REGISTERED 2nd patch remove blk_mq_register_dev which is usesless. 3rd patch fix the issue by changing the sync method, please refer to the comment. Jianchao Wang (3) block: add helper interface blk_queue_registered blk-mq: cleanup blk_mq_register_dev block: fix the lock inversion caused by kobject_del under sysfs_lock block/blk-mq-sysfs.c | 80 +++++++++++++++++++++++++++++++------------------- block/blk-mq.h | 3 ++ block/blk-sysfs.c | 43 ++++++++++++++------------- block/blk-wbt.c | 4 --- block/elevator.c | 5 ++-- include/linux/blk-mq.h | 3 -- include/linux/blkdev.h | 4 ++- 7 files changed, 82 insertions(+), 60 deletions(-) Thanks Jianchao