From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicolas Dichtel Subject: Re: [PATCH 1/2] ipv6: avoid blackhole and prohibited entries upon prefix purge [v2] Date: Mon, 07 Jan 2013 11:25:15 +0100 Message-ID: <50EAA28B.1080300@6wind.com> References: <0CC79564-4AF2-42F9-8D06-1BCC912A1AF7@ipflavors.com> <1357415941.1678.4163.camel@edumazet-glaptop> <2A507F9D-3D53-475F-8FA9-9E6CFEE9C97A@ipflavors.com> Reply-To: nicolas.dichtel@6wind.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "netdev@vger.kernel.org" , Eric Dumazet , yoshfuji@linux-ipv6.org, davem@davemloft.net To: Romain KUNTZ Return-path: Received: from mail-la0-f48.google.com ([209.85.215.48]:64037 "EHLO mail-la0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750933Ab3AGKZS (ORCPT ); Mon, 7 Jan 2013 05:25:18 -0500 Received: by mail-la0-f48.google.com with SMTP id ej20so15175680lab.35 for ; Mon, 07 Jan 2013 02:25:17 -0800 (PST) In-Reply-To: <2A507F9D-3D53-475F-8FA9-9E6CFEE9C97A@ipflavors.com> Sender: netdev-owner@vger.kernel.org List-ID: Le 05/01/2013 22:44, Romain KUNTZ a =E9crit : > Mobile IPv6 provokes a kernel Oops since commit 64c6d08e (ipv6: > del unreachable route when an addr is deleted on lo), because > ip6_route_lookup() may also return blackhole and prohibited > entry. However, these entries have a NULL rt6i_table argument, > which provokes an Oops in __ip6_del_rt() when trying to lock > rt6i_table->tb6_lock. > > Beside, when purging a prefix, blakhole and prohibited entries > should not be selected because they are not what we are looking > for. > > We fix this by adding two new lookup flags (RT6_LOOKUP_F_NO_BLK_HOLE > and RT6_LOOKUP_F_NO_PROHIBIT) in order to ensure that such entries > are skipped during lookup and that the correct entry is returned. > > [v2]: use 'goto out;' instead of 'goto again;' to avoid unnecessary > oprations on rt (as suggested by Eric Dumazet). > > Signed-off-by: Romain Kuntz > --- > include/net/ip6_route.h | 2 ++ > net/ipv6/addrconf.c | 4 +++- > net/ipv6/fib6_rules.c | 4 ++++ > 3 files changed, 9 insertions(+), 1 deletions(-) > > diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h > index 27d8318..3c93743 100644 > --- a/include/net/ip6_route.h > +++ b/include/net/ip6_route.h > @@ -30,6 +30,8 @@ struct route_info { > #define RT6_LOOKUP_F_SRCPREF_TMP 0x00000008 > #define RT6_LOOKUP_F_SRCPREF_PUBLIC 0x00000010 > #define RT6_LOOKUP_F_SRCPREF_COA 0x00000020 > +#define RT6_LOOKUP_F_NO_BLK_HOLE 0x00000040 > +#define RT6_LOOKUP_F_NO_PROHIBIT 0x00000080 > > /* > * rt6_srcprefs2flags() and rt6_flags2srcprefs() translate > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index 408cac4a..1891e23 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -948,7 +948,9 @@ static void ipv6_del_addr(struct inet6_ifaddr *if= p) > fl6.flowi6_oif =3D ifp->idev->dev->ifindex; > fl6.daddr =3D prefix; > rt =3D (struct rt6_info *)ip6_route_lookup(net, &fl6, > - RT6_LOOKUP_F_IFACE); > + RT6_LOOKUP_F_IFACE | > + RT6_LOOKUP_F_NO_BLK_HOLE | > + RT6_LOOKUP_F_NO_PROHIBIT); > > if (rt !=3D net->ipv6.ip6_null_entry && Is it not simpler to test the result here (net->ipv6.ip6_blk_hole_entry= and net->ipv6.ip6_prohibit_entry) like for the null_entry? It will also avoid adding more flags.