Messages in this thread | | | From | John Stultz <> | Date | Wed, 9 Aug 2017 16:44:26 -0700 | Subject | Re: unregister_netdevice: waiting for eth0 to become free. Usage count = 1 |
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On Wed, Aug 9, 2017 at 4:34 PM, Cong Wang <xiyou.wangcong@gmail.com> wrote: > (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.
Correct, once I get into the state it lasts until a reboot.
> 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.
So with 4.13-rc3/4 I seem to trigger it easily, often with the first unplug of the USB eth adapter.
But as I get back closer to 4.12, it seemingly becomes harder to trigger, but sometimes still happens.
So far, I've not been able to trigger it with 4.12.
I don't think network namespaces are involved? Though its out of my area, so AOSP may be using them these days. Is there a simple way to check?
I'll also do another bisection to see if the bad point moves back any further.
thanks -john
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