From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Buehler Subject: Re: kernel panic in fib_rules_lookup [2.6.27.7 vendor-patched] Date: Sat, 23 Oct 2010 11:40:35 -0400 Message-ID: <4CC301F3.5010504@cox.net> References: <1286905245.2703.3.camel@edumazet-laptop> <4CBF2A3F.2070108@cox.net> <1287612353.2545.11.camel@edumazet-laptop> <4CC1F47C.9020104@cox.net> <1287805487.2658.5.camel@edumazet-laptop> <1287846669.2658.247.camel@edumazet-laptop> <1287847465.2658.266.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, David Daney To: Eric Dumazet Return-path: Received: from eastrmmtao104.cox.net ([68.230.240.46]:43737 "EHLO eastrmmtao104.cox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757581Ab0JWPkh (ORCPT ); Sat, 23 Oct 2010 11:40:37 -0400 In-Reply-To: <1287847465.2658.266.camel@edumazet-laptop> Sender: netdev-owner@vger.kernel.org List-ID: Eric Dumazet wrote: > > David Daney added a nudge_writes(), actually doing a "syncw" > instruction, and this seems to be the smp_wmb() this platform should be > using in the first place, not a pure compiler barrier (barrier()) > > So Joe, you might want to change the smp_wmb() call in > rcu_assign_pointer() by the nudge_writes() call, and see what happens... > > > I think Daney is Cavium's Octeon LINUX guru from the posts I've seen so he would definitely know the platform. I'm not sure I quite understand what you are saying but it sounds as though you are saying that smp_wb is not doing a syncw and that sounds *totally* broken -- snycw is what the low-level Cavium SDK uses for memory barriers all over the place. Joe Buehler