Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757786AbZFSLPj (ORCPT ); Fri, 19 Jun 2009 07:15:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756909AbZFSLPP (ORCPT ); Fri, 19 Jun 2009 07:15:15 -0400 Received: from stinky.trash.net ([213.144.137.162]:63323 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756452AbZFSLPO (ORCPT ); Fri, 19 Jun 2009 07:15:14 -0400 Message-ID: <4A3B7340.50602@trash.net> Date: Fri, 19 Jun 2009 13:15:12 +0200 From: Patrick McHardy User-Agent: Mozilla-Thunderbird 2.0.0.19 (X11/20090103) MIME-Version: 1.0 To: Eric Dumazet CC: Ingo Molnar , David Miller , Thomas Gleixner , torvalds@linux-foundation.org, akpm@linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Pablo Neira Ayuso Subject: Re: [PATCH] netfilter: conntrack: death_by_timeout() fix References: <20090615.050449.144947903.davem@davemloft.net> <20090616091538.GA4184@elte.hu> <20090616.034752.226811527.davem@davemloft.net> <20090616105304.GA3579@elte.hu> <20090616122415.GA16630@elte.hu> <20090617092152.GA17449@elte.hu> <4A38C2F3.3000009@gmail.com> <20090617110803.GA10175@elte.hu> <20090618052356.GA18722@elte.hu> <4A39D778.9020607@cosmosbay.com> <4A3A0D45.8090806@trash.net> <4A3A5599.4080906@trash.net> <4A3A6143.3040607@gmail.com> <4A3A66CC.4090205@trash.net> <4A3AC3B3.2030002@gmail.com> In-Reply-To: <4A3AC3B3.2030002@gmail.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1000 Lines: 25 Eric Dumazet wrote: > [PATCH] netfilter: conntrack: death_by_timeout() fix > > death_by_timeout() might delete a conntrack from hash list > and insert it in dying list. > > nf_ct_delete_from_lists(ct); > nf_ct_insert_dying_list(ct); > > I believe a (lockless) reader could *catch* ct while doing a lookup > and miss the end of its chain. > (nulls lookup algo must check the null value at the end of lookup and > should restart if the null value is not the expected one. > cf Documentation/RCU/rculist_nulls.txt for details) > > We need to change nf_conntrack_init_net() and use a different "null" value, > guaranteed not being used in regular lists. Choose very large values, since > hash table uses [0..size-1] null values. Applied, thanks Eric. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/