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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+c54f8e94e6bba03b04e9@syzkaller.appspotmail.com,
        Al Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH 4.4 051/160] gfs2_meta: ->mount() can get NULL dev_name
Date:   Mon, 19 Nov 2018 17:28:10 +0100
Message-Id: <20181119162636.515140005@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Al Viro <viro@zeniv.linux.org.uk>

commit 3df629d873f8683af6f0d34dfc743f637966d483 upstream.

get in sync with mount_bdev() handling of the same

Reported-by: syzbot+c54f8e94e6bba03b04e9@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/gfs2/ops_fstype.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1353,6 +1353,9 @@ static struct dentry *gfs2_mount_meta(st
 	struct path path;
 	int error;
 
+	if (!dev_name || !*dev_name)
+		return ERR_PTR(-EINVAL);
+
 	error = kern_path(dev_name, LOOKUP_FOLLOW, &path);
 	if (error) {
 		pr_warn("path_lookup on %s returned error %d\n",