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 C3AF6C3DA7A for ; Fri, 6 Jan 2023 01:57:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229970AbjAFB5U (ORCPT ); Thu, 5 Jan 2023 20:57:20 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36326 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229455AbjAFB5R (ORCPT ); Thu, 5 Jan 2023 20:57:17 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7A0C13D75; Thu, 5 Jan 2023 17:57:15 -0800 (PST) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Np5z35QDhzJrFL; Fri, 6 Jan 2023 09:55:59 +0800 (CST) Received: from [10.174.151.185] (10.174.151.185) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Fri, 6 Jan 2023 09:57:12 +0800 Subject: Re: [PATCH] mce: fix missing stack-dumping in mce_panic() To: "Luck, Tony" CC: "x86@kernel.org" , "hpa@zytor.com" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "dave.hansen@linux.intel.com" , Borislav Petkov References: <20221202163728.392509-1-linmiaohe@huawei.com> <5cf492bf-9807-a091-6ac2-a953fce276da@huawei.com> <1e97c11d-99b6-c06f-b67f-c56ba6653d27@huawei.com> <276c9e6b-d647-6f7f-7bd1-c1f45ca23261@huawei.com> From: Miaohe Lin Message-ID: Date: Fri, 6 Jan 2023 09:57:12 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.151.185] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/1/4 5:12, Luck, Tony wrote: >>> I guess the original issue that commit was fixing is to save that >>> redundant oops message but Tony seems to want to see it now and I'm not >>> sure how much we care about 80x50 screens nowadays... :-) > Many thanks for your thought. :) > I want a stack dump for the specific case of a recoverable machine check caused by > poison consumption in kernel code that doesn't have an extable[] entry for a recovery > path. That's a potential candidate for future kernel change to make that recoverable Sure, in this case a stack dump will be really helpful. We can gather these stack dumps and try to make the most frequent machine check scene recoverable. > (if the code path seems common enough to warrant the churn), and there is some > plausible way for s/w to "recover"). > > For most other machine checks the dump is very likely useless. E.g. some CPU core stalled > so that the system generates a broadcast machine check because instructions are not > being retired on that CPU core. In this case the machine check "monarch" is almost certainly > some innocent bystander that was executing normally. Stack dump from that CPU is going > to tell you nothing about the machine check. Agree. A stack dump won't be helpful in this case. But I tend to keep the stack dump in case it would be helpful and also make mce_panic() dumps the stack as expected. What do you think? Thanks, Miaohe Lin