From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [PATCH] Fix 2.6.34-rc1 regression in disable_ipv6 support Date: Thu, 09 Dec 2010 11:09:34 -0800 Message-ID: References: <4CFD0AF0.9090809@hp.com> <4D000B6D.1060708@hp.com> <20101208154932.5bc4b254@nehalam> <4D00F58A.2050307@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , netdev@vger.kernel.org, Mahesh Kelkar , Lorenzo Colitti , YOSHIFUJI Hideaki , Stephen Hemminger , stable@kernel.org To: Brian Haley Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:41932 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756580Ab0LITJo (ORCPT ); Thu, 9 Dec 2010 14:09:44 -0500 In-Reply-To: <4D00F58A.2050307@hp.com> (Brian Haley's message of "Thu, 09 Dec 2010 10:28:10 -0500") Sender: netdev-owner@vger.kernel.org List-ID: Brian Haley writes: > On 12/08/2010 11:16 PM, Eric W. Biederman wrote: >> Finding the real bug is beyond me right now, but fixing the regression >> in disable_ipv6 is simple. We can just delete ::1 when we bring down >> the loopback interface, and it will be restored automatically when we >> bring the loopback interface back up. > > Hi Eric, > > This would work as well, same check, different way. But that looks like less of an obvious magic exception. The only address it is safe to ignore on is ::1, because we always restore it when we bring the loopback interface up. Long term we really do want to keep the loopback address. But that actually requires finding and fixing what is broken in ipv6. So let's please keep this a line that we can easily remove. It isn't like interfaces coming up and down are a fast path where every cycle counts. We just need to be reasonably efficient. Eric