From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934077Ab0HXXXp (ORCPT ); Tue, 24 Aug 2010 19:23:45 -0400 Received: from kroah.org ([198.145.64.141]:40835 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932544Ab0HXXBT (ORCPT ); Tue, 24 Aug 2010 19:01:19 -0400 X-Mailbox-Line: From gregkh@clark.site Tue Aug 24 15:45:02 2010 Message-Id: <20100824224502.418117364@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 24 Aug 2010 15:44:18 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Wengang Wang , Joel Becker Subject: [013/114] ocfs2/dlm: fix a dead lock In-Reply-To: <20100824224610.GA5424@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.35-stable review patch. If anyone has any objections, please let us know. ------------------ From: Wengang Wang commit 6d98c3ccb52f692f1a60339dde7c700686a5568b upstream. When we have to take both dlm->master_lock and lockres->spinlock, take them in order lockres->spinlock and then dlm->master_lock. The patch fixes a violation of the rule. We can simply move taking dlm->master_lock to where we have dropped res->spinlock since when we access res->state and free mle memory we don't need master_lock's protection. Signed-off-by: Wengang Wang Signed-off-by: Joel Becker Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/dlm/dlmmaster.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -3050,8 +3050,6 @@ int dlm_migrate_request_handler(struct o /* check for pre-existing lock */ spin_lock(&dlm->spinlock); res = __dlm_lookup_lockres(dlm, name, namelen, hash); - spin_lock(&dlm->master_lock); - if (res) { spin_lock(&res->spinlock); if (res->state & DLM_LOCK_RES_RECOVERING) { @@ -3069,14 +3067,15 @@ int dlm_migrate_request_handler(struct o spin_unlock(&res->spinlock); } + spin_lock(&dlm->master_lock); /* ignore status. only nonzero status would BUG. */ ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name, namelen, migrate->new_master, migrate->master); -unlock: spin_unlock(&dlm->master_lock); +unlock: spin_unlock(&dlm->spinlock); if (oldmle) {