--- a/drivers/usb/misc/yurex.c
+++ b/drivers/usb/misc/yurex.c
@@ -178,6 +178,10 @@ static void yurex_interrupt(struct urb *
 	}
 
 exit:
+	if (!usb_get_intfdata(dev->interface)) {
+		dev_info(&dev->interface->dev, "%s unbound\n", __func__);
+		return;
+	}
 	retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
 	if (retval) {
 		dev_err(&dev->interface->dev, "%s - usb_submit_urb failed: %d\n",
@@ -309,11 +313,15 @@ static void yurex_disconnect(struct usb_
 
 	dev = usb_get_intfdata(interface);
 	usb_set_intfdata(interface, NULL);
+	dev_info(&interface->dev, "%s\n", __func__);
 
 	/* give back our minor */
 	usb_deregister_dev(interface, &yurex_class);
 
 	/* prevent more I/O from starting */
+	dev_info(&interface->dev, "Before poison\n");
+	usb_poison_urb(dev->urb);
+	dev_info(&interface->dev, "After poison\n");
 	mutex_lock(&dev->io_mutex);
 	dev->interface = NULL;
 	mutex_unlock(&dev->io_mutex);