From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: ctnetlink kernel dump while running multiple libnfct clients Date: Wed, 30 Mar 2011 01:11:54 +0200 Message-ID: <4D92673A.5070108@netfilter.org> References: <4D908351.5010407@netfilter.org> <4D91B083.2000001@netfilter.org> <4D925614.2000909@netfilter.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Netfilter Developer Mailing List To: Sam Roberts Return-path: Received: from mail.us.es ([193.147.175.20]:53596 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751989Ab1C2XMA (ORCPT ); Tue, 29 Mar 2011 19:12:00 -0400 In-Reply-To: Sender: netfilter-devel-owner@vger.kernel.org List-ID: On 30/03/11 00:44, Sam Roberts wrote: > When this happened, I was running the prototype conntracker, and > several instances of conntrack -E (for each table). I typed a > conntrack -L command, and the kernel died after I hit ENTER. Could be > unrelated to that, but seems suspiciously coincidental that the > backtrace shown reflects something I did (it looks related to printing > conntracks). Still, you would know better than me what the kernel does > when things go wrong. I think I've got the problematic scenario: the master ct is released while there are still user-space expectations. In that case, the expectations still point to the master, once they've been released. Once the expectations expire, we dereference to the master ct which is not valid anymore. I'll send a patch to fix this.