From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: echo > 0 .../disable_ipv6 broken in 2.6.37-rc4 Date: Wed, 08 Dec 2010 13:29:52 -0800 Message-ID: References: <4CFD0AF0.9090809@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, Mahesh Kelkar , Lorenzo Colitti To: Brian Haley Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]:58732 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751676Ab0LHV35 (ORCPT ); Wed, 8 Dec 2010 16:29:57 -0500 In-Reply-To: <4CFD0AF0.9090809@hp.com> (Brian Haley's message of "Mon, 06 Dec 2010 11:10:24 -0500") Sender: netdev-owner@vger.kernel.org List-ID: Brian Haley writes: > On 12/05/2010 07:24 PM, Eric W. Biederman wrote: >> >> In 2.6.37-rc4 ipv6 can be disabled not enabled. >> The last kernel I have tested and know this works on is 2.6.33. >> >> To reproduce: >> ~ # ip link set lo up >> ~ # ping6 ::1 >> PING ::1(::1) 56 data bytes >> 64 bytes from ::1: icmp_seq=1 ttl=64 time=0.026 ms >> ^C >> --- ::1 ping statistics --- >> 1 packets transmitted, 1 received, 0% packet loss, time 782ms >> rtt min/avg/max/mdev = 0.026/0.026/0.026/0.000 ms >> ~ # echo 1 > /proc/sys/net/ipv6/conf/lo/disable_ipv6 >> ~ # ping6 ::1 >> connect: Network is unreachable >> ~ # echo 0 > /proc/sys/net/ipv6/conf/lo/disable_ipv6 >> ~ # ping6 ::1 >> connect: Network is unreachable >> >> >> I intend to poke at this a little more but at the moment >> I am drawing a blank at what is going on. > > It should just be calling addrconf_notify() with either NETDEV_UP > or NETDEV_DOWN. Does the address not come back? Or the route? The address never went away, and I don't think we have a route to ::1. Playing with this a little more if I delete the address and then bounce the interface ping ::1 works again. So something is just not getting reinitialized. Unfortunately I don't see anything obvious. I'm still scratching my head. >> I intend to keep poking at this but if anyone can figure this out >> before I do I would be greatly appreciative. > > I'm pulling the latest tree now, my 2.6.32.24 system is running fine, so > it's something after that. Agreed. I don't have problems on 2.6.33 either, but because of overload I haven't been doing regular testing of the kernels inbetween. Eric