From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752207Ab3K3QqB (ORCPT ); Sat, 30 Nov 2013 11:46:01 -0500 Received: from mail-pd0-f175.google.com ([209.85.192.175]:54839 "EHLO mail-pd0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751327Ab3K3Qp6 (ORCPT ); Sat, 30 Nov 2013 11:45:58 -0500 Message-ID: <1385829955.5352.40.camel@edumazet-glaptop2.roam.corp.google.com> Subject: Re: [PATCH] ipv6: fix possible seqlock deadlock in ip6_finish_output2 From: Eric Dumazet To: Hannes Frederic Sowa Cc: jongman.heo@samsung.com, David Miller , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" Date: Sat, 30 Nov 2013 08:45:55 -0800 In-Reply-To: <20131129053944.GH24171@order.stressinduktion.org> References: <13025162.118881385612276530.JavaMail.weblogic@epv6ml01> <1385659390.5352.20.camel@edumazet-glaptop2.roam.corp.google.com> <1385661082.5352.34.camel@edumazet-glaptop2.roam.corp.google.com> <20131128192231.GE24171@order.stressinduktion.org> <20131129053944.GH24171@order.stressinduktion.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2013-11-29 at 06:39 +0100, Hannes Frederic Sowa wrote: > IPv6 stats are 64 bits and thus are protected with a seqlock. By not > disabling bottom-half we could deadlock here if we don't disable bh and > a softirq reentrantly updates the same mib. > > Cc: Eric Dumazet > Signed-off-by: Hannes Frederic Sowa > --- Acked-by: Eric Dumazet (Note that the seqlock is only for 32bit arches)