Re: 2.6.38 containers bug: Infinite loop in /proc/sys/net/ipv6/neigh/neigh/neigh...

From: Rob Landley
Date: Wed Mar 30 2011 - 06:16:39 EST


On 03/30/2011 04:01 AM, David Miller wrote:
> From: Rob Landley <rlandley@xxxxxxxxxxxxx>
> Date: Wed, 30 Mar 2011 03:29:16 -0500
>
>> In the host context a find on /proc completes, but inside an lxc
>> container a find on /proc never completes, due to the endless loop in
>> the title. (It's not a symlink, it seems to be a cross linked directory.)
>>
>> This is vanilla 2.6.38, I can attach my .config if you think it'd help.
>> (The container's the lxc debian sid template but that's probably not
>> relevant.)
>
> Please CC: netdev@xxxxxxxxxxxxxxx when a bug might be related to
> networking, as is obviously the case here.
>
> This bug should be fixed by the following patch:
>
> --------------------
> commit 9d2a8fa96a44ba242de3a6f56acaef7a40a97b97
> Author: Eric W. Biederman <ebiederm@xxxxxxxxxxxxxxxxxx>
> Date: Mon Mar 21 18:23:34 2011 -0700
>
> net ipv6: Fix duplicate /proc/sys/net/ipv6/neigh directory entries.
>
> When I was fixing issues with unregisgtering tables under /proc/sys/net/ipv6/neigh
> by adding a mount point it appears I missed a critical ordering issue, in the
> ipv6 initialization. I had not realized that ipv6_sysctl_register is called
> at the very end of the ipv6 initialization and in particular after we call
> neigh_sysctl_register from ndisc_init.
>
> "neigh" needs to be initialized in ipv6_static_sysctl_register which is
> the first ipv6 table to initialized, and definitely before ndisc_init.
> This removes the weirdness of duplicate tables while still providing a
> "neigh" mount point which prevents races in sysctl unregistering.
>
> This was initially reported at https://bugzilla.kernel.org/show_bug.cgi?id=31232
> Reported-by: sunkan@xxxxxxxx
> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>


Yes, that fixed it. Pinging the stable guys to make sure this goes in a
dot release.

Thanks,

Rob
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