Set the disconnected flag before releasing the data interface in case
netdev registration fails to avoid having the disconnect callback try to
deregister the never registered netdev (and trigger a WARN_ON()).
Fixes: 87cf65601e17 ("USB host CDC Phonet network interface driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
 
        err = register_netdev(dev);
        if (err) {
+               /* Set disconnected flag so that disconnect() returns early. */
+               pnd->disconnected = 1;
                usb_driver_release_interface(&usbpn_driver, data_intf);
                goto out;
        }