From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: echo > 0 .../disable_ipv6 broken in 2.6.37-rc4 Date: Sun, 05 Dec 2010 16:24:22 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Brian Haley , Mahesh Kelkar , Lorenzo Colitti To: Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]:35236 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752224Ab0LFBIb (ORCPT ); Sun, 5 Dec 2010 20:08:31 -0500 Sender: netdev-owner@vger.kernel.org List-ID: 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. I have tried reverting the last change to the ipv6 logic and that doesn't make a difference. commit 64e724f62ab743d55229cd5e27ec8b068b68eb16 Author: Brian Haley Date: Tue Jul 20 10:34:30 2010 +0000 ipv6: Don't add routes to ipv6 disabled interfaces. If the interface has IPv6 disabled, don't add a multicast or link-local route since we won't be adding a link-local address. Reported-by: Mahesh Kelkar Signed-off-by: Brian Haley Signed-off-by: David S. Miller I intend to keep poking at this but if anyone can figure this out before I do I would be greatly appreciative. Eric