From patchwork Wed Aug 26 22:12:09 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 7080331 Return-Path: X-Original-To: patchwork-ocfs2-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 4D156BEEC1 for ; Wed, 26 Aug 2015 22:12:23 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6497A208DE for ; Wed, 26 Aug 2015 22:12:22 +0000 (UTC) Received: from userp1040.oracle.com (userp1040.oracle.com [156.151.31.81]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3CFD7208DA for ; Wed, 26 Aug 2015 22:12:21 +0000 (UTC) Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t7QMCEPv007001 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 26 Aug 2015 22:12:14 GMT Received: from oss.oracle.com (oss-old-reserved.oracle.com [137.254.22.2]) by aserv0021.oracle.com (8.13.8/8.13.8) with ESMTP id t7QMCD0B025176 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 26 Aug 2015 22:12:13 GMT Received: from localhost ([127.0.0.1] helo=lb-oss.oracle.com) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1ZUivV-0006v3-LF; Wed, 26 Aug 2015 15:12:13 -0700 Received: from userv0022.oracle.com ([156.151.31.74]) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1ZUivU-0006um-0Y for ocfs2-devel@oss.oracle.com; Wed, 26 Aug 2015 15:12:12 -0700 Received: from aserp1020.oracle.com (aserp1020.oracle.com [141.146.126.67]) by userv0022.oracle.com (8.13.8/8.13.8) with ESMTP id t7QMCBXG006423 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 26 Aug 2015 22:12:11 GMT Received: from userp2030.oracle.com (userp2030.oracle.com [156.151.31.89]) by aserp1020.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t7QMCA3J009829 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Wed, 26 Aug 2015 22:12:11 GMT Received: from pps.filterd (userp2030.oracle.com [127.0.0.1]) by userp2030.oracle.com (8.15.0.59/8.15.0.59) with SMTP id t7QM8oC6045581 for ; Wed, 26 Aug 2015 22:12:10 GMT Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) by userp2030.oracle.com with ESMTP id 1whb7vgedk-1 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 26 Aug 2015 22:12:10 +0000 Received: from akpm3.mtv.corp.google.com (unknown [216.239.45.65]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 59B00DF9; Wed, 26 Aug 2015 22:12:09 +0000 (UTC) Date: Wed, 26 Aug 2015 15:12:09 -0700 From: akpm@linux-foundation.org To: ocfs2-devel@oss.oracle.com, akpm@linux-foundation.org, jiangyiwen@huawei.com, jlbec@evilplan.org, joseph.qi@huawei.com, mfasheh@suse.com Message-ID: <55de39b9.MBCx0fXNJOuDOCFO%akpm@linux-foundation.org> User-Agent: Heirloom mailx 12.5 6/20/10 MIME-Version: 1.0 X-Proofpoint-SPF-Result: pass X-Proofpoint-SPF-Record: v=spf1 ip4:140.211.169.12/30 include:_spf.google.com ~all X-ServerName: mail.linuxfoundation.org X-Proofpoint-Virus-Version: vendor=nai engine=5700 definitions=7905 signatures=670626 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1507310000 definitions=main-1508260346 Subject: [Ocfs2-devel] [patch 18/28] ocfs2: avoid access invalid address when read o2dlm debug messages X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Source-IP: aserv0021.oracle.com [141.146.126.233] X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Yiwen Jiang Subject: ocfs2: avoid access invalid address when read o2dlm debug messages The following case will lead to a lockres is freed but is still in use. cat /sys/kernel/debug/o2dlm/locking_state dlm_thread lockres_seq_start -> lock dlm->track_lock -> get resA resA->refs decrease to 0, call dlm_lockres_release, and wait for "cat" unlock. Although resA->refs is already set to 0, increase resA->refs, and then unlock lock dlm->track_lock -> list_del_init() -> unlock -> free resA In such a race case, invalid address access may occurs. So we should delete list res->tracking before resA->refs decrease to 0. Signed-off-by: Yiwen Jiang Reviewed-by: Joseph Qi Cc: Joel Becker Cc: Mark Fasheh Signed-off-by: Andrew Morton Signed-off-by: Mark Fasheh --- fs/ocfs2/dlm/dlmmaster.c | 22 +++++++++++----------- fs/ocfs2/dlm/dlmthread.c | 10 ++++++++++ 2 files changed, 21 insertions(+), 11 deletions(-) diff -puN fs/ocfs2/dlm/dlmmaster.c~ocfs2-avoid-access-invalid-address-when-read-o2dlm-debug-messages fs/ocfs2/dlm/dlmmaster.c --- a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-avoid-access-invalid-address-when-read-o2dlm-debug-messages +++ a/fs/ocfs2/dlm/dlmmaster.c @@ -498,16 +498,6 @@ static void dlm_lockres_release(struct k mlog(0, "destroying lockres %.*s\n", res->lockname.len, res->lockname.name); - spin_lock(&dlm->track_lock); - if (!list_empty(&res->tracking)) - list_del_init(&res->tracking); - else { - mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n", - res->lockname.len, res->lockname.name); - dlm_print_one_lock_resource(res); - } - spin_unlock(&dlm->track_lock); - atomic_dec(&dlm->res_cur_count); if (!hlist_unhashed(&res->hash_node) || @@ -795,8 +785,18 @@ lookup: dlm_lockres_grab_inflight_ref(dlm, tmpres); spin_unlock(&tmpres->spinlock); - if (res) + if (res) { + spin_lock(&dlm->track_lock); + if (!list_empty(&res->tracking)) + list_del_init(&res->tracking); + else + mlog(ML_ERROR, "Resource %.*s not " + "on the Tracking list\n", + res->lockname.len, + res->lockname.name); + spin_unlock(&dlm->track_lock); dlm_lockres_put(res); + } res = tmpres; goto leave; } diff -puN fs/ocfs2/dlm/dlmthread.c~ocfs2-avoid-access-invalid-address-when-read-o2dlm-debug-messages fs/ocfs2/dlm/dlmthread.c --- a/fs/ocfs2/dlm/dlmthread.c~ocfs2-avoid-access-invalid-address-when-read-o2dlm-debug-messages +++ a/fs/ocfs2/dlm/dlmthread.c @@ -211,6 +211,16 @@ static void dlm_purge_lockres(struct dlm __dlm_unhash_lockres(dlm, res); + spin_lock(&dlm->track_lock); + if (!list_empty(&res->tracking)) + list_del_init(&res->tracking); + else { + mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n", + res->lockname.len, res->lockname.name); + __dlm_print_one_lock_resource(res); + } + spin_unlock(&dlm->track_lock); + /* lockres is not in the hash now. drop the flag and wake up * any processes waiting in dlm_get_lock_resource. */ if (!master) {