Comment 28 for bug 1711407

> Is there any way for a non-kernel-dev type to see exactly which resource
> unregister_netdevice is waiting for? (Or does it only keep track of usage count?)

not really, no. It's simply waiting for its reference count to drop to 0, and just broadcasts unregister events periodically hoping that everyone with a reference is listening and does whatever they need to do to drop their references. In this case the socket's dst actually is listening, but the way the dst handles it assumes that the loopback interface will never, ever unregister - the dst shifts its reference count from the interface going down, to its netns's loopback interface. If the interface going down is the netns's loopback interface, then that reference shift doesn't help, of course.

So no, there is no simple way for you to tell what it's waiting for.