Re: kernel stack trace using conntrack

Le vendredi 19 février 2010 à 03:18 +0100, Pablo Neira Ayuso a écrit :

Patrick McHardy wrote:

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Pablo Neira Ayuso wrote:

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Patrick McHardy wrote:

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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.

I have slightly tested the following patch here. I think it should fix
the problem.

We can revisit ctnetlink_change_helper() later, I think there's some
code there that can be refactorized.

Let me know if you're OK with it.

I sucessfuly tested your patch Pablo, thanks.

Signed-off-by: Eric Dumazet <redacted>