From mboxrd@z Thu Jan 1 00:00:00 1970 From: chenweilong Subject: Re: [PATCH] ipv6: don't call addrconf_dst_alloc again when enable lo Date: Thu, 2 Jan 2014 15:58:22 +0800 Message-ID: <52C51C1E.9040603@huawei.com> References: <1371352470-3226-1-git-send-email-gaofeng@cn.fujitsu.com> <20130619.230532.1329281330568271336.davem@davemloft.net> <20131231035718.GB27636@order.stressinduktion.org> <52C4FDBE.5030607@huawei.com> <20140102065429.GB22494@order.stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: David Miller , , , , Hannes Frederic Sowa Return-path: Received: from szxga02-in.huawei.com ([119.145.14.65]:8602 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750721AbaABH6h (ORCPT ); Thu, 2 Jan 2014 02:58:37 -0500 In-Reply-To: <20140102065429.GB22494@order.stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-ID: On 2014/1/2 14:54, Hannes Frederic Sowa wrote: > On Thu, Jan 02, 2014 at 01:48:46PM +0800, chenweilong wrote: >> On 2013/12/31 11:57, Hannes Frederic Sowa wrote: >>> On Wed, Jun 19, 2013 at 11:05:32PM -0700, David Miller wrote: >>>> From: Gao feng >>>> Date: Sun, 16 Jun 2013 11:14:30 +0800 >>>> >>>>> If we disable all of the net interfaces, and enable >>>>> un-lo interface before lo interface, we already allocated >>>>> the addrconf dst in ipv6_add_addr. So we shouldn't allocate >>>>> it again when we enable lo interface. >>>>> >>>>> Otherwise the message below will be triggered. >>>>> unregister_netdevice: waiting for sit1 to become free. Usage count = 1 >>>>> >>>>> This problem is introduced by commit 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f >>>>> "net IPv6 : Fix broken IPv6 routing table after loopback down-up" >>>>> >>>>> Signed-off-by: Gao feng >>>> >>>> This is the second such regression added by that commit :-/ >>>> >>>> Applied and queue up for -stable, thanks. >>> >>> Hmm, and this change also has a regression and breaks the original fix. :/ >>> >>> https://bugzilla.kernel.org/show_bug.cgi?id=67951 >>> >>> I tried to track it down but it seems pretty complicated. Maybe we have to >>> special-case the take-down of the loopback device. >>> >>> >>> >> >> When I did the tests,If 'ifconfig lo down',all IPv6 connection broken, >> but IPv4 connection were still OK. >> >> Is it designed like that or a bug? > > This seems to solve the loopback up/down problem, but there are still > some issues with up/down of interfaces and routing table interactions. > > We enable routes over interfaces when interface is actually down and > kick manually specified on-link routes when we actually should try to > keep them and just disable them. > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index 6c16345..61d752a 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -2629,8 +2629,10 @@ static void init_loopback(struct net_device *dev) > if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE)) > continue; > > - if (sp_ifa->rt) > + if (sp_ifa->rt) { > + ip6_ins_rt(sp_ifa->rt); > continue; > + } > > sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, false); > > > . > I test the patch,it has the problem Gao feng reported. How about this: diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index d5fa5b8..5e2db6e 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -2609,10 +2609,13 @@ static void init_loopback(struct net_device *dev) if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE)) continue; - if (sp_ifa->rt) - continue; + if (sp_ifa->rt && sp_ifa->rt->dst.dev == dev){ + ip6_del_rt(sp_ifa->rt); + } sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, false); /* Failure cases are ignored */