diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index 0f49479..412f977 100644
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -450,9 +450,8 @@
 	if (ld->ops->open) {
 		int ret;
                 /* BTM here locks versus a hangup event */
-		tty_lock_nested(); /* always held here already */
+		WARN_ON(!tty_locked());
 		ret = ld->ops->open(tty);
-		tty_unlock();
 		return ret;
 	}
 	return 0;