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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Ashish Samant" <ashish.samant@oracle.com>,
        "Joel Becker" <jlbec@evilplan.org>,
        "Jun Piao" <piaojun@huawei.com>,
        "Junxiao Bi" <junxiao.bi@oracle.com>,
        "Changwei Ge" <ge.changwei@h3c.com>,
        "Joseph Qi" <jiangqi903@gmail.com>,
        "Mark Fasheh" <mark@fasheh.com>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.626041140@decadent.org.uk>
Subject: [PATCH 3.16 302/328] ocfs2: fix locking for res->tracking and
 dlm->tracking_list
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ashish Samant <ashish.samant@oracle.com>

commit cbe355f57c8074bc4f452e5b6e35509044c6fa23 upstream.

In dlm_init_lockres() we access and modify res->tracking and
dlm->tracking_list without holding dlm->track_lock.  This can cause list
corruptions and can end up in kernel panic.

Fix this by locking res->tracking and dlm->tracking_list with
dlm->track_lock instead of dlm->spinlock.

Link: http://lkml.kernel.org/r/1529951192-4686-1-git-send-email-ashish.samant@oracle.com
Signed-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Acked-by: Joseph Qi <jiangqi903@gmail.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 fs/ocfs2/dlm/dlmmaster.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -599,9 +599,9 @@ static void dlm_init_lockres(struct dlm_
 
 	res->last_used = 0;
 
-	spin_lock(&dlm->spinlock);
+	spin_lock(&dlm->track_lock);
 	list_add_tail(&res->tracking, &dlm->tracking_list);
-	spin_unlock(&dlm->spinlock);
+	spin_unlock(&dlm->track_lock);
 
 	memset(res->lvb, 0, DLM_LVB_LEN);
 	memset(res->refmap, 0, sizeof(res->refmap));