+ /* To prevent network device cleanup code from dereferencing
+ * loopback devices or network devices that have been freed
+ * wait here for all pending unregistrations to complete,
+ * before unregistring the loopback device and allowing the
+ * network namespace be freed.
+ *
+ * The netdev todo list containing all network devices
+ * unregistrations that happen in default_device_exit_batch
+ * will run in the rtnl_unlock() at the end of
+ * default_device_exit_batch.
+ */
+ rtnl_lock_unregistering(net_list);