Re: kernel stack trace using conntrack

[Patrick McHardy <kaber@trash.net>]

Pablo Neira Ayuso wrote:
> Patrick McHardy wrote:
>>>> Pablo, please let me know whether you want me to apply this.
>>> ctnetlink_change_helper() also calls nf_ct_ext_add() for conntracks that
>>> are confirmed (in case of a helper update for an existing conntrack).
>>> That would also trigger the assertion. If we want to support helper
>>> assignation via ctnetlink for existing conntracks, we will need to add
>>> locking to the conntrack extension infrastructure to avoid races.
>>>
>>> I don't see a clear solution for this yet.
>> I see, this is indeed a problem. Since the helper is known at the
>> first event, we could restrict this to only allow manual assignment
>> for newly created conntracks. Most helpers probably can't properly
>> cope with connections not seen from the beginning anyways.
> 
> Indeed, changing the helper in the middle of the road doesn't make too
> much sense to me either. I can send you a patch for this along today,
> I'll find some spare time to do it.

Great, thanks Pablo.