From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] ipv6: fix RTNL assert fail in DAD Date: Wed, 19 Mar 2014 13:53:19 -0400 (EDT) Message-ID: <20140319.135319.2039055704156238608.davem@davemloft.net> References: <20140318175406.78339ffe@nehalam.linuxnetplumber.net> <20140319.001736.730011705431992209.davem@davemloft.net> <20140318235811.0d8f230a@nehalam.linuxnetplumber.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: hannes@stressinduktion.org, netdev@vger.kernel.org To: stephen@networkplumber.org Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:37008 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751389AbaCSRxV (ORCPT ); Wed, 19 Mar 2014 13:53:21 -0400 In-Reply-To: <20140318235811.0d8f230a@nehalam.linuxnetplumber.net> Sender: netdev-owner@vger.kernel.org List-ID: From: Stephen Hemminger Date: Tue, 18 Mar 2014 23:58:11 -0700 > On Wed, 19 Mar 2014 00:17:36 -0400 (EDT) > David Miller wrote: > >> From: Stephen Hemminger >> Date: Tue, 18 Mar 2014 17:54:06 -0700 >> >> > On Tue, 18 Mar 2014 01:29:08 +0100 >> > Hannes Frederic Sowa wrote: >> > >> >> I wonder if we should put the whole ipv6_ifa_notify infrastructure in a >> >> workqueue? I don't like that either and it could add subtile races. >> > >> > That is option, might be some call chains that already have rtnl_lock held. >> >> There are TAHI ipv6 conformance tests that expect state changes to be >> precisely synchronous. >> >> And frankly it's pretty reasonable to send two packets back to back, >> one which causes the state change and one which tests if the state >> change happened, and expect that to work. > > It is more the timer based state changes that are problematic because > they aren't acquire RTNL. Ok, the timer stuff could run from a workqueue just fine.