diff --git a/drivers/isdn/hisax/st5481_usb.c b/drivers/isdn/hisax/st5481_usb.c
index 4ada66b8b6792e2eb1025479a610fb6fb5d980c3..427a8b0520f5aee14684503f208e5faa6f841d1b 100644
--- a/drivers/isdn/hisax/st5481_usb.c
+++ b/drivers/isdn/hisax/st5481_usb.c
@@ -342,7 +342,7 @@ void st5481_release_usb(struct st5481_adapter *adapter)
 	usb_kill_urb(intr->urb);
 	kfree(intr->urb->transfer_buffer);
 	usb_free_urb(intr->urb);
-	ctrl->urb = NULL;
+	intr->urb = NULL;
 }
 
 /*