diff --git a/drivers/usb/serial/visor.c b/drivers/usb/serial/visor.c
index 1aa5d20..8e2d6dd 100644
--- a/drivers/usb/serial/visor.c
+++ b/drivers/usb/serial/visor.c
@@ -513,7 +513,8 @@
 			tty_kref_put(tty);
 		}
 		spin_lock(&priv->lock);
-		priv->bytes_in += available_room;
+		if (tty)
+			priv->bytes_in += available_room;
 
 	} else {
 		spin_lock(&priv->lock);