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 X-Spam-Level: X-Spam-Status: No, score=-10.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53489C4338F for ; Tue, 27 Jul 2021 08:46:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3BA89611C4 for ; Tue, 27 Jul 2021 08:46:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235988AbhG0Iqz (ORCPT ); Tue, 27 Jul 2021 04:46:55 -0400 Received: from goliath.siemens.de ([192.35.17.28]:49805 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235919AbhG0Iqz (ORCPT ); Tue, 27 Jul 2021 04:46:55 -0400 Received: from mail2.sbs.de (mail2.sbs.de [192.129.41.66]) by goliath.siemens.de (8.15.2/8.15.2) with ESMTPS id 16R8k8QQ007948 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 27 Jul 2021 10:46:09 +0200 Received: from [167.87.33.191] ([167.87.33.191]) by mail2.sbs.de (8.15.2/8.15.2) with ESMTP id 16R8k6jj011473; Tue, 27 Jul 2021 10:46:07 +0200 Subject: Re: sched: Unexpected reschedule of offline CPU#2! To: Henning Schild , Thomas Gleixner Cc: Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Borislav Petkov , Guenter Roeck , xenomai@xenomai.org References: <20190727164450.GA11726@roeck-us.net> <20190729093545.GV31381@hirez.programming.kicks-ass.net> <20190729101349.GX31381@hirez.programming.kicks-ass.net> <20190729104745.GA31398@hirez.programming.kicks-ass.net> <20190729205059.GA1127@roeck-us.net> <20190816193208.GA29478@roeck-us.net> <20210727100018.19d61165@md1za8fc.ad001.siemens.net> From: Jan Kiszka Message-ID: <745f219e-1593-4fbd-fa7f-1719ef6f444d@siemens.com> Date: Tue, 27 Jul 2021 10:46:06 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20210727100018.19d61165@md1za8fc.ad001.siemens.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Henning, don't top-post ;)] On 27.07.21 10:00, Henning Schild via Xenomai wrote: > Was this ever resolved and if so can someone please point me to the > patches? I started digging a bit but could not yet find how that > continued. > > I am seeing similar or maybe the same problem on 4.19.192 with the > ipipe patch from the xenomai project applied. > Before blaming the usual suspects, I have a general ordering question on mainline below. > regards, > Henning > > Am Sat, 17 Aug 2019 22:21:48 +0200 > schrieb Thomas Gleixner : > >> On Fri, 16 Aug 2019, Guenter Roeck wrote: >>> On Fri, Aug 16, 2019 at 12:22:22PM +0200, Thomas Gleixner wrote: >>>> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c >>>> index 75fea0d48c0e..625627b1457c 100644 >>>> --- a/arch/x86/kernel/process.c >>>> +++ b/arch/x86/kernel/process.c >>>> @@ -601,6 +601,7 @@ void stop_this_cpu(void *dummy) >>>> /* >>>> * Remove this CPU: >>>> */ >>>> + set_cpu_active(smp_processor_id(), false); >>>> set_cpu_online(smp_processor_id(), false); >>>> disable_local_APIC(); >>>> mcheck_cpu_clear(this_cpu_ptr(&cpu_info)); >>>> >>> No luck. The problem is still seen with this patch applied on top of >>> the mainline kernel (commit a69e90512d9def6). >> >> Yeah, was a bit too naive .... >> >> We actually need to do the full cpuhotplug dance for a regular >> reboot. In the panic case, there is nothing we can do about. I'll >> have a look tomorrow. >> What is supposed to prevent the following in mainline: CPU 0 CPU 1 CPU 2 native_stop_other_cpus send_IPI_allbutself ... sysvec_reboot stop_this_cpu set_cpu_online(false) native_smp_send_reschedule(1) if (cpu_is_offline(1)) ... Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux