For hso serial devices, two cancel_work_sync were missing in the
disconnect method.
Signed-off-by: Olivier Sobrie <olivier@sobrie.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
                        mutex_lock(&serial->parent->mutex);
                        serial->parent->usb_gone = 1;
                        mutex_unlock(&serial->parent->mutex);
+                       cancel_work_sync(&serial_table[i]->async_put_intf);
+                       cancel_work_sync(&serial_table[i]->async_get_intf);
                        hso_serial_tty_unregister(serial);
                        kref_put(&serial_table[i]->ref, hso_serial_ref_free);
                        set_serial_by_index(i, NULL);