}
 
        down(&open_sem);
+       if (!usb_get_intfdata(intf)) {
+               up(&open_sem);
+               return;
+       }
        acm->dev = NULL;
-       usb_set_intfdata (intf, NULL);
+       usb_set_intfdata(acm->control, NULL);
+       usb_set_intfdata(acm->data, NULL);
 
        tasklet_disable(&acm->urb_task);
 
        for (i = 0; i < ACM_NRB; i++)
                usb_buffer_free(usb_dev, acm->readsize, acm->rb[i].base, acm->rb[i].dma);
 
-       usb_driver_release_interface(&acm_driver, acm->data);
+       usb_driver_release_interface(&acm_driver, intf == acm->control ? acm->data : intf);
 
        if (!acm->used) {
                acm_tty_unregister(acm);