On Wed, Aug 9, 2017 at 4:44 PM, John Stultz <john.stultz@xxxxxxxxxx> wrote: > On Wed, Aug 9, 2017 at 4:34 PM, Cong Wang <xiyou.wangcong@xxxxxxxxx> wrote: >> (Cc'ing Wei whose commit was blamed) >> >> On Mon, Aug 7, 2017 at 2:15 PM, John Stultz <john.stultz@xxxxxxxxxx> wrote: >>> On Mon, Aug 7, 2017 at 2:05 PM, John Stultz <john.stultz@xxxxxxxxxx> 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 Hi John, Does your USB adapter get an IPv6 address? If you see the problem starts to happen on commit 9514528d92d4cbe086499322370155ed69f5d06c, could you try reverting all the following commits: (from new to old) 1eb04e7c9e63 net: reorder all the dst flags a4c2fd7f7891 net: remove DST_NOCACHE flag b2a9c0ed75a3 net: remove DST_NOGC flag 5b7c9a8ff828 net: remove dst gc related code db916649b5dd ipv6: get rid of icmp6 dst garbage collector 587fea741134 ipv6: mark DST_NOGC and remove the operation of dst_free() ad65a2f05695 ipv6: call dst_hold_safe() properly 9514528d92d4 ipv6: call dst_dev_put() properly and try if it starts to work? By only reverting 9514528d92d4 definitely won't work as all the later commits depend on this one. Thanks a lot. Wei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
