Multiple cores/race conditions in IPv6 RA

[Andrey V. Elsukov]

On 08.12.15 08:32, Jason wrote:
> Hi,
> 
> It appears the IPv6 router advertisement code paths were written fairly
> lockless, assuming you would never process multiples concurrently.  We
> are seeing multiple page faults in various places processing the
> messages and modifying the routing table.  We have multiple L3 devices
> and multiple v6 blocks broadcasting these messages to hardware with dual
> uplinks in the same VLAN, which I believe is making us susceptible to
> this.  Though I believe the dual uplink is all that's required for this,
> as it can be seen in configurations with a single v6 block.
> 
> We are running stable/10 @ r285800, and it doesn't appear anything
> relevant has changed since then.  Our other widely deployed version is
> 8.3-RELEASE, which does not see this issue.  Upon bumping a machine from
> 8.3 -> 10 we can see it start to exhibit this behavior.  The only change
> I see that might be relevant is r243148, but these cores are relatively
> rare, so testing is tough without a considerable deployment.  So
> basically I'm hoping someone with a trained eye can send us in the right
> direction before we go down that road.

Hi,

some time ago Mark Johnston has published there the patch related to
this problem:
https://lists.freebsd.org/pipermail/freebsd-net/2013-February/034682.html

Maybe Mark has something to say about it.

-- 
WBR, Andrey V. Elsukov

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 538 bytes
Desc: OpenPGP digital signature
URL: <http://lists.freebsd.org/pipermail/freebsd-net/attachments/20151209/b61ee1a3/attachment.sig>