From: Guoqing Jiang <gqjiang@suse.com>
Date: Tue, 16 May 2017 06:01:25 +0000 (+0800)
Subject: md-cluster: fix potential lock issue in add_new_disk
X-Git-Tag: v4.1.52~252
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b8e2096553ae1f1ec689d8444994fdea7ecf3b9b;p=thirdparty%2Fkernel%2Fstable.git

md-cluster: fix potential lock issue in add_new_disk

[ Upstream commit 2dffdc0724004f38f5e39907747b53e4b0d80e59 ]

The add_new_disk returns with communication locked if
__sendmsg returns failure, fix it with call unlock_comm
before return.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
CC: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---

diff --git a/drivers/md/md-cluster.c b/drivers/md/md-cluster.c
index 4eb5cb18f98da..f490382173b67 100644
--- a/drivers/md/md-cluster.c
+++ b/drivers/md/md-cluster.c
@@ -850,8 +850,10 @@ static int add_new_disk_start(struct mddev *mddev, struct md_rdev *rdev)
 	cmsg.raid_slot = rdev->desc_nr;
 	lock_comm(cinfo);
 	ret = __sendmsg(cinfo, &cmsg);
-	if (ret)
+	if (ret) {
+		unlock_comm(cinfo);
 		return ret;
+	}
 	cinfo->no_new_dev_lockres->flags |= DLM_LKF_NOQUEUE;
 	ret = dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_EX);
 	cinfo->no_new_dev_lockres->flags &= ~DLM_LKF_NOQUEUE;