[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CADvbK_dgEa5g0ynY4F8pX6LuuBwW4e42rK_TFuRhY1=2G5zinw@mail.gmail.com>
Date: Thu, 1 Feb 2018 01:49:12 +0100
From: Xin Long <lucien.xin@...il.com>
To: David Ahern <dsahern@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>,
Cong Wang <xiyou.wangcong@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
David Miller <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Willem de Bruijn <willemb@...gle.com>,
Jakub Kicinski <jakub.kicinski@...ronome.com>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
netdev <netdev@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Alexey Kuznetsov <kuznet@....inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
syzkaller <syzkaller@...glegroups.com>,
Dan Streetman <ddstreet@...onical.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: net: hang in unregister_netdevice: waiting for lo to become free
On Tue, Jan 30, 2018 at 11:59 PM, David Ahern <dsahern@...il.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@...gle.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@...il.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@...il.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.
Powered by blists - more mailing lists