staging: lustre: lustre: obdclass: obd_mount.c: Fix NULL dereference

OBD_ALLOC_PTR(uuid) invokes kmalloc, which may return NULL. This fix
adds a check before dereferencing such pointer.
Signed-off-by: NKumar Amit Mehta <gmate.amit@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/obd_mount.c

@@ -376,6 +376,11 @@ int lustre_start_mgc(struct super_block *sb)
 
 	/* Random uuid for MGC allows easier reconnects */
 	OBD_ALLOC_PTR(uuid);
+	if (!uuid) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+
 	ll_generate_random_uuid(uuidc);
 	class_uuid_unparse(uuidc, uuid);