From: Hannes Frederic Sowa <hannes@stressinduktion•org>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: Bob Falken <NetFestivalHaveFun@gmx•com>,
Julian Anastasov <ja@ssi•bg>,
netdev@vger•kernel.org, kaber@trash•net, tgraf@suug•ch
Subject: Re: Multicast routing stops functioning after 4G multicast packets recived.
Date: Fri, 10 Jan 2014 08:43:25 +0100 [thread overview]
Message-ID: <20140110074325.GC17866@order.stressinduktion.org> (raw)
In-Reply-To: <1389339179.31367.98.camel@edumazet-glaptop2.roam.corp.google.com>
On Thu, Jan 09, 2014 at 11:32:59PM -0800, Eric Dumazet wrote:
> On Fri, 2014-01-10 at 08:10 +0100, Hannes Frederic Sowa wrote:
> > On Thu, Jan 09, 2014 at 11:01:46PM -0800, Eric Dumazet wrote:
> > > Its not clear to me why you expand ipmr_fib_lookup()
> > >
> > > Is there something wrong with existing code ?
> >
> > There are three users of ipmr_fib_lookup, two of them are in rcu_read_lock
> > section, one is not.
> >
> > ipmr_fib_lookup does not pass down arg.rule reference, so I don't have a
> > chance to call fib_rule_put(arg.rule) on it. Thus I left ipmr_fib_lookup,
> > just adding FIB_LOOKUP_NOREF and expanding ipmr_fib_lookup into the
> > other function so I still have access to arg.rule to decrement the
> > reference counter.
> >
> > Do you agree?
>
> Hmm, I see the problem now.
>
> What about adding a parameter to ipmr_fib_lookup(),
> to keep its spirit ?
>
> ipmr_fib_lookup(net, &fl4, &mrt);
> ->
> ipmr_fib_lookup(net, &fl4, &mrt, &rule);
>
> Since ipmr_rt_fib_lookup() has the same rule leak, no ?
No, ipmr_rt_fib_lookup is fine. This function gets called only from
rcu read locked section and we don't take table reference because of
FIB_LOOKUP_NOREF, so we don't need to put reference counter on arg.table.
We could add the additional argument, just ignoring it in ipmr_rt_fib_lookup.
>
> Its a bit late here, so maybe following is just stupid :
> Cant we do the fib_rule_put() inside ipmr_fib_lookup() ?
We could add bool noref to ipmr_fib_lookup indicating we want to drop
reference to rule just after lookup.
I'll check if freeing a rule has additional side-effects on dependencies
in reg_vif_xmit. That would be a nice solution actually, thanks!
next prev parent reply other threads:[~2014-01-10 7:43 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-09 20:14 Multicast routing stops functioning after 4G multicast packets recived Bob Falken
2014-01-10 6:36 ` Hannes Frederic Sowa
2014-01-10 7:01 ` Eric Dumazet
2014-01-10 7:10 ` Hannes Frederic Sowa
2014-01-10 7:32 ` Eric Dumazet
2014-01-10 7:43 ` Hannes Frederic Sowa [this message]
2014-01-10 7:50 ` Hannes Frederic Sowa
2014-01-12 7:42 ` Hannes Frederic Sowa
2014-01-13 0:56 ` Eric Dumazet
2014-01-13 1:45 ` [PATCH net] net: avoid reference counter overflows on fib_rules in multicast forwarding Hannes Frederic Sowa
2014-01-13 15:18 ` Eric Dumazet
2014-01-13 23:38 ` Hannes Frederic Sowa
2014-01-15 1:40 ` David Miller
-- strict thread matches above, loose matches on Subject: below --
2014-01-12 0:25 Multicast routing stops functioning after 4G multicast packets recived Bob Falken
2014-01-07 17:01 Bob Falken
2014-01-07 17:43 ` Hannes Frederic Sowa
2014-01-07 20:11 ` Hannes Frederic Sowa
2014-01-07 20:20 ` Hannes Frederic Sowa
2014-01-07 20:26 ` Eric Dumazet
2014-01-07 20:29 ` Hannes Frederic Sowa
2014-01-04 18:53 Bob Falken
2013-12-21 22:35 Bob Falken
2014-01-03 7:37 ` Hannes Frederic Sowa
2013-12-19 16:28 Bob Falken
2013-12-19 17:24 ` Eric Dumazet
2013-12-19 17:32 ` Hannes Frederic Sowa
2013-12-22 3:10 ` Hannes Frederic Sowa
2013-12-19 14:48 Bob Falken
2013-12-19 15:09 ` Hannes Frederic Sowa
2013-12-19 15:15 ` Ben Greear
2013-12-19 15:48 ` Hannes Frederic Sowa
2014-01-04 19:55 ` Julian Anastasov
2014-01-04 23:38 ` Hannes Frederic Sowa
2014-01-05 8:56 ` Julian Anastasov
2014-01-05 10:41 ` Hannes Frederic Sowa
2014-01-05 19:12 ` Eric Dumazet
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