From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90CA6C43334 for ; Wed, 6 Jul 2022 12:40:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232025AbiGFMkS (ORCPT ); Wed, 6 Jul 2022 08:40:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230362AbiGFMkS (ORCPT ); Wed, 6 Jul 2022 08:40:18 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58C28252AA; Wed, 6 Jul 2022 05:40:17 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1o94K7-0004EF-24; Wed, 06 Jul 2022 14:40:07 +0200 Date: Wed, 6 Jul 2022 14:40:07 +0200 From: Florian Westphal To: Will Deacon Cc: Florian Westphal , Kajetan Puchalski , Pablo Neira Ayuso , Jozsef Kadlecsik , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Mel Gorman , lukasz.luba@arm.com, dietmar.eggemann@arm.com, mark.rutland@arm.com, broonie@kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, stable@vger.kernel.org, regressions@lists.linux.dev, linux-kernel@vger.kernel.org, peterz@infradead.org Subject: Re: [Regression] stress-ng udp-flood causes kernel panic on Ampere Altra Message-ID: <20220706124007.GB7996@breakpoint.cc> References: <20220702205651.GB15144@breakpoint.cc> <20220705105749.GA711@willie-the-truck> <20220705110724.GB711@willie-the-truck> <20220705112449.GA931@willie-the-truck> <20220706120201.GA7996@breakpoint.cc> <20220706122246.GI2403@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220706122246.GI2403@willie-the-truck> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Will Deacon wrote: > On Wed, Jul 06, 2022 at 02:02:01PM +0200, Florian Westphal wrote: > > + /* ->status and ->timeout loads must happen after refcount increase */ > > + smp_rmb(); > > Sorry I didn't suggest this earlier, but if all of these smp_rmb()s are > for upgrading the ordering from refcount_inc_not_zero() then you should > use smp_acquire__after_ctrl_dep() instead. It's the same under the hood, > but it illustrates what's going on a bit better. Ok, I can replace it and send a v2, no problem.