ocfs2: fix double free in user_cluster_connect()

user_cluster_disconnect() frees "conn->cc_private" which is "lc" but then
the error handling frees "lc" a second time.  Set "lc" to NULL on this
path to avoid a double free.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: c994c2e ("ocfs2: use the new DLM operation callbacks while requesting new lockspace")
Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: Joseph Qi <[email protected]>
Reviewed-by: Goldwyn Rodrigues <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: Junxiao Bi <[email protected]>
Cc: Changwei Ge <[email protected]>
Cc: Jun Piao <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Dan Carpenter

fs/ocfs2/stack_user.c

@@ -1011,6 +1011,7 @@ static int user_cluster_connect(struct ocfs2_cluster_connection *conn)
 			printk(KERN_ERR "ocfs2: Could not determine"
 					" locking version\n");
 			user_cluster_disconnect(conn);
+			lc = NULL;
 			goto out;
 		}
 		wait_event(lc->oc_wait, (atomic_read(&lc->oc_this_node) > 0));