netdev - Re: kernel stack trace using conntrack

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Message-ID: <1266582824.3136.1.camel@edumazet-laptop>
Date:	Fri, 19 Feb 2010 13:33:44 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Pablo Neira Ayuso <pablo@...filter.org>
Cc:	Patrick McHardy <kaber@...sh.net>,
	Ramblewski David <David.Ramblewski@...sorigin.com>,
	"netfilter-devel@...r.kernel.org" <netfilter-devel@...r.kernel.org>,
	netdev <netdev@...r.kernel.org>
Subject: Re: kernel stack  trace using conntrack

Le vendredi 19 février 2010 à 03:18 +0100, Pablo Neira Ayuso a écrit :
> Patrick McHardy wrote:
> > 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.
> 
> 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 <eric.dumazet@...il.com>



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