netdev - Re: [net-next,v7] net: ipv6: Make address flushing on ifdown optional

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <56D72F95.3030101@gmail.com>
Date:	Wed, 2 Mar 2016 10:23:17 -0800
From:	David Ahern <dsahern@...il.com>
To:	Andrey Wagin <avagin@...il.com>, netdev@...r.kernel.org
Subject: Re: [net-next,v7] net: ipv6: Make address flushing on ifdown optional

On 3/2/16 10:01 AM, Andrey Wagin wrote:
> Hi David,
>
> We execute CRIU test on linux-next. On the current linux-next kernel
> they hangs on creating a network namespace.
>
> The kernel log contains many massages like this:
> [ 1036.122108] unregister_netdevice: waiting for lo to become free.
> Usage count = 2
> [ 1046.165156] unregister_netdevice: waiting for lo to become free.
> Usage count = 2
> [ 1056.210287] unregister_netdevice: waiting for lo to become free.
> Usage count = 2
>
> I tried to revert this patch and the bug disappeared.
>
> Here is a set of commands to reproduce this bug:
>
> [root@...ux-next-test linux-next]# uname -a
> Linux linux-next-test 4.5.0-rc6-next-20160301+ #3 SMP Wed Mar 2
> 17:32:18 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
>
> [root@...ux-next-test ~]# unshare -n
> [root@...ux-next-test ~]# ip link set up dev lo
> [root@...ux-next-test ~]# ip a
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
> group default qlen 1
>      link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>      inet 127.0.0.1/8 scope host lo
>         valid_lft forever preferred_lft forever
>      inet6 ::1/128 scope host
>         valid_lft forever preferred_lft forever
> [root@...ux-next-test ~]# logout
> [root@...ux-next-test ~]# unshare -n

Thanks for reporting -- with reproduction commands. I will post patch as 
soon as I have time to look into it.

David