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* Re: [net-next,v7] net: ipv6: Make address flushing on ifdown optional
@ 2016-03-02 18:01 Andrey Wagin
  2016-03-02 18:23 ` David Ahern
  0 siblings, 1 reply; 2+ messages in thread
From: Andrey Wagin @ 2016-03-02 18:01 UTC (permalink / raw)
  To: netdev, David Ahern

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@linux-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@linux-next-test ~]# unshare -n
[root@linux-next-test ~]# ip link set up dev lo
[root@linux-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@linux-next-test ~]# logout
[root@linux-next-test ~]# unshare -n



^Z
...

Thanks,
Andrew

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [net-next,v7] net: ipv6: Make address flushing on ifdown optional
  2016-03-02 18:01 [net-next,v7] net: ipv6: Make address flushing on ifdown optional Andrey Wagin
@ 2016-03-02 18:23 ` David Ahern
  0 siblings, 0 replies; 2+ messages in thread
From: David Ahern @ 2016-03-02 18:23 UTC (permalink / raw)
  To: Andrey Wagin, netdev

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@linux-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@linux-next-test ~]# unshare -n
> [root@linux-next-test ~]# ip link set up dev lo
> [root@linux-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@linux-next-test ~]# logout
> [root@linux-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

^ permalink raw reply	[flat|nested] 2+ messages in thread

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