Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1

[Cong Wang <xiyou.wangcong@gmail.com>]

(Cc'ing Wei whose commit was blamed)

On Mon, Aug 7, 2017 at 2:15 PM, John Stultz <john.stultz@linaro.org> wrote:
> On Mon, Aug 7, 2017 at 2:05 PM, John Stultz <john.stultz@linaro.org> wrote:
>> So, with recent testing with my HiKey board, I've been noticing some
>> quirky behavior with my USB eth adapter.
>>
>> Basically, pluging the usb eth adapter in and then removing it, when
>> plugging it back in I often find that its not detected, and the system
>> slowly spits out the following message over and over:
>>   unregister_netdevice: waiting for eth0 to become free. Usage count = 1
>
> The other bit is that after this starts printing, the board will no
> longer reboot (it hangs continuing to occasionally print the above
> message), and I have to manually reset the device.
>

So this warning is not temporarily shown but lasts until a reboot,
right? If so it is a dst refcnt leak.

How reproducible is it for you? From my reading, it seems always
reproduced when you unplug and plug your usb eth interface?
Is there anything else involved? For example, network namespace.

Thanks.