From: Julian Anastasov <ja@ssi.bg>
To: Tim Gardner <tim.gardner@canonical.com>
Cc: kaber@trash.net, linux-kernel@vger.kernel.org,
David Miller <davem@davemloft.net>,
netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org,
coreteam@netfilter.org, netdev@vger.kernel.org
Subject: Re: [PATCH] Check net->nfnl for NULL in ctnetlink_conntrack_event to, avoid Oops on container destroy
Date: Mon, 12 Sep 2011 23:40:42 +0300 (EEST) [thread overview]
Message-ID: <alpine.LFD.2.00.1109122256450.1592@ja.ssi.bg> (raw)
In-Reply-To: <4E6E4961.9070802@canonical.com>
Hello,
On Mon, 12 Sep 2011, Tim Gardner wrote:
> Patrick,
>
> I received this patch from a developer that uses lxc and network name spaces.
> I don't know the locking semantics well enough for CT to judge whether this
> fix is sufficient. Bug info can be found at
> http://bugs.launchpad.net/bugs/843892 . See comment #7 for his analysis.
We found same problems triggered by IPVS during
subsys cleanup:
http://marc.info/?l=netfilter-devel&m=130765388528399&w=2
It is a general problem for modules that register
callbacks to the netfilter core. nfnetlink is such example
with a mix of global (ctnl_notifier) and per-net (nfnetlink_net_ops)
registrations. During net cleanup the module must be prepared
to be called by core because the core cleanup happens later.
So, may be rcu_dereference under rcu lock is needed for
some functions (nfnetlink_has_listeners, nfnetlink_send) but
such changes should be audited by nfnetlink developers.
Using rcu_assign_pointer for net->nfnl without corresponding
rcu_dereference looks like a problem.
Regards
--
Julian Anastasov <ja@ssi.bg>
next prev parent reply other threads:[~2011-09-12 20:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-12 18:03 Tim Gardner
2011-09-12 18:42 ` Tim Gardner
2011-09-12 20:40 ` Julian Anastasov [this message]
2011-09-14 12:31 ` Pablo Neira Ayuso
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