Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933583AbbENS7F (ORCPT ); Thu, 14 May 2015 14:59:05 -0400 Received: from mail-wg0-f43.google.com ([74.125.82.43]:34044 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932807AbbENS7C (ORCPT ); Thu, 14 May 2015 14:59:02 -0400 Message-ID: <5554F073.4080501@6wind.com> Date: Thu, 14 May 2015 20:58:59 +0200 From: Nicolas Dichtel Reply-To: nicolas.dichtel@6wind.com Organization: 6WIND User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Michal Kubecek , "David S. Miller" CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , roopa Subject: Re: [PATCH net v2 2/2] ipv6: fix ECMP route replacement References: In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2300 Lines: 66 Le 13/05/2015 21:59, Michal Kubecek a écrit : > When replacing an IPv6 multipath route with "ip route replace", i.e. > NLM_F_CREATE | NLM_F_REPLACE, fib6_add_rt2node() replaces only first > matching route without fixing its siblings, resulting in corrupted > siblings linked list; removing one of the siblings can then end in an > infinite loop. > > Replacing the whole set of nexthops does IMHO make more sense than > replacing a random one. We also need to remove the NLM_F_REPLACE flag > after replacing old nexthops by first new so that each subsequent > nexthop does not replace previous one. > > Fixes: 51ebd3181572 ("ipv6: add support of equal cost multipath (ECMP)") > Signed-off-by: Michal Kubecek > --- > net/ipv6/ip6_fib.c | 17 ++++++++++++++--- > net/ipv6/route.c | 8 +++++--- > 2 files changed, 19 insertions(+), 6 deletions(-) > > diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c > index 96dbffff5a24..abf4e4e5bdab 100644 > --- a/net/ipv6/ip6_fib.c > +++ b/net/ipv6/ip6_fib.c > @@ -815,6 +815,8 @@ add: > } > > } else { > + struct rt6_info *next; > + > if (!found) { > if (add) > goto add; > @@ -828,15 +830,24 @@ add: > > *ins = rt; > rt->rt6i_node = fn; > - rt->dst.rt6_next = iter->dst.rt6_next; > + > + /* skip potential siblings */ > + next = iter->dst.rt6_next; > + while (next && next->rt6i_metric == rt->rt6i_metric) > + next = next->dst.rt6_next; I wonder if we should not loop over the siblings list here (rt->rt6i_siblings). Only routes that match 'rt6_qualify_for_ecmp()' are siblings. > + rt->dst.rt6_next = next; > + > atomic_inc(&rt->rt6i_ref); > inet6_rt_notify(RTM_NEWROUTE, rt, info); > if (!(fn->fn_flags & RTN_RTINFO)) { > info->nl_net->ipv6.rt6_stats->fib_route_nodes++; > fn->fn_flags |= RTN_RTINFO; > } > - fib6_purge_rt(iter, fn, info->nl_net); > - rt6_release(iter); > + while (iter != next) { > + fib6_purge_rt(iter, fn, info->nl_net); > + rt6_release(iter); > + iter = iter->dst.rt6_next; > + } Same here. -- 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/