Messages in this thread | | | Subject | Re: net: hang in unregister_netdevice: waiting for lo to become free | From | Tommi Rantala <> | Date | Tue, 20 Feb 2018 09:56:38 +0200 |
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On 19.02.2018 20:59, Dmitry Vyukov wrote: > On Sat, Feb 3, 2018 at 1:15 PM, Xin Long <lucien.xin@gmail.com> wrote: >>>> On 1/30/18 1:57 PM, David Ahern wrote: >>>>> On 1/30/18 1:08 PM, Daniel Borkmann wrote: >>>>>> On 01/30/2018 07:32 PM, Cong Wang wrote: >>>>>>> On Tue, Jan 30, 2018 at 4:09 AM, Dmitry Vyukov <dvyukov@google.com> wrote: >>>>>>>> Hello, >>>>>>>> >>>>>>>> The following program creates a hang in unregister_netdevice. >>>>>>>> cleanup_net work hangs there forever periodically printing >>>>>>>> "unregister_netdevice: waiting for lo to become free. Usage count = 3" >>>>>>>> and creation of any new network namespaces hangs forever. >>>>>>> >>>>>>> Interestingly, this is not reproducible on net-next. >>>>>> >>>>>> The most recent change on netns refcnt was 4ee806d51176 ("net: tcp: close >>>>>> sock if net namespace is exiting") in net/net-next from 5 days ago, maybe >>>>>> fixed due to that? >>>>>> >>>>> >>>>> This appears to be the commit introducing the refcnt leak: >>>>> >>>>> $ git bisect bad >>>>> dbc2b5e9a09e9a6664679a667ff81cff6e5f2641 is the first bad commit >>>>> commit dbc2b5e9a09e9a6664679a667ff81cff6e5f2641 >>>>> Author: Xin Long <lucien.xin@gmail.com> >>>>> Date: Fri May 12 14:39:52 2017 +0800 >>>>> >>>>> sctp: fix src address selection if using secondary addresses for ipv6 >>>>> >>>>> >>>>> v4.14 is bad. Running bisect in the background while doing other things.... >>>>> >>>> >>>> Interesting. The commit that avoids the refcnt leak is >>>> >>>> commit 955ec4cb3b54c7c389a9f830be7d3ae2056b9212 >>>> Author: David Ahern <dsahern@gmail.com> >>>> Date: Wed Jan 24 19:45:29 2018 -0800 >>>> >>>> net/ipv6: Do not allow route add with a device that is down >>>> >>>> That commit does not intentionally address the problem so it is just >>>> masking the problematic code introduced by the commit above. >>> Thanks, David A. >>> >>> I'm still on a trip. will look into this asap. >> >> Alexey and Tommi already had the patches for this issue on >> both SCTP v4 and v6 dst_get, Thanks. > > > > Is this meant to be fixed already? I am still seeing this on the > latest upstream tree. >
These two commits are in v4.16-rc1:
commit 4a31a6b19f9ddf498c81f5c9b089742b7472a6f8 Author: Tommi Rantala <tommi.t.rantala@nokia.com> Date: Mon Feb 5 21:48:14 2018 +0200
sctp: fix dst refcnt leak in sctp_v4_get_dst ... Fixes: 410f03831 ("sctp: add routing output fallback") Fixes: 0ca50d12f ("sctp: fix src address selection if using secondary addresses")
commit 957d761cf91cdbb175ad7d8f5472336a4d54dbf2 Author: Alexey Kodanev <alexey.kodanev@oracle.com> Date: Mon Feb 5 15:10:35 2018 +0300
sctp: fix dst refcnt leak in sctp_v6_get_dst() ... Fixes: dbc2b5e9a09e ("sctp: fix src address selection if using secondary addresses for ipv6")
I guess we missed something if it's still reproducible.
I can check it later this week, unless someone else beat me to it.
Tommi
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