From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: conntrack, suspicious RCU usage Date: Thu, 12 Jan 2012 03:30:44 +0100 Message-ID: <20120112023044.GB12255@1984> References: <201201111025.50994.hans.schillstrom@ericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "netfilter-devel@vger.kernel.org" To: Hans Schillstrom Return-path: Received: from mail.us.es ([193.147.175.20]:38139 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751071Ab2ALCau (ORCPT ); Wed, 11 Jan 2012 21:30:50 -0500 Content-Disposition: inline In-Reply-To: <201201111025.50994.hans.schillstrom@ericsson.com> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On Wed, Jan 11, 2012 at 10:25:50AM +0100, Hans Schillstrom wrote: > Hello > I got this the first time using conntrack -L when there is a lot of traffic. > It doesn't result in any thing bad yet. > > Is this a know thing ? No, you have been the first to spot this. > or should I dig into it.. > > I'm running the latest and greatest conntrack / netfilter tools and libs. > > =============================== > [ INFO: suspicious RCU usage. ] > ------------------------------- > /home/hans/evip.git/kvm/net-next.git/include/net/netfilter/nf_conntrack_l3proto.h:92 suspicious rcu_dereference_check() usage! We were using rcu in the table dumping time ago, but we had to replace rcu by spinlocks. ctnetlink_dump_tuples is used in both RCU context and spinlock context, this seems to be the problem. it seems I didn't enable RCU read lock verification in my kernels. I'll do it to catch up this sort of problems. thanks for the report.