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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no 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 B751FC55185 for ; Wed, 22 Apr 2020 14:49:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F5092076E for ; Wed, 22 Apr 2020 14:49:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726979AbgDVOtN (ORCPT ); Wed, 22 Apr 2020 10:49:13 -0400 Received: from mx2.suse.de ([195.135.220.15]:51414 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726819AbgDVOtM (ORCPT ); Wed, 22 Apr 2020 10:49:12 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 9ED44AA55; Wed, 22 Apr 2020 14:49:10 +0000 (UTC) Message-ID: <1587566950.9537.107.camel@suse.cz> Subject: Re: [BISECTED]: Kernel panic (was: Linux 5.7-rc2) From: Giovanni Gherdovich To: Dave Kleikamp , Peter Zijlstra , Linus Torvalds , Harald Arnesen Cc: Ingo Molnar , "Rafael J. Wysocki" , Linux Kernel Mailing List Date: Wed, 22 Apr 2020 16:49:10 +0200 In-Reply-To: <5b9531e1-e0ae-cf5d-84f2-6bbb5c2cd089@oracle.com> References: <428bac87-b6dd-0867-c8f8-622cd606de3e@skogtun.org> <20200421212347.GV2483@worktop.programming.kicks-ass.net> <1587546150.9537.84.camel@suse.cz> <5b9531e1-e0ae-cf5d-84f2-6bbb5c2cd089@oracle.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2020-04-22 at 09:12 -0500, Dave Kleikamp wrote: > On 4/22/20 4:02 AM, Giovanni Gherdovich wrote: > > Linus, Peter: > > > > the panic seen by Harald Arnesen (and Dave Kleikamp) is unrelated to > > virtualization, and happens on all machines that have a CPU with less than 4 > > physical cores. It's a very serious (and very stupid) bug in the original > > version of my code and is fixed by patch 2/4 "x86, sched: Account for CPUs > > with less than 4 cores in freq. invariance" in the series > > > > https://lore.kernel.org/lkml/20200416054745.740-1-ggherdovich@suse.cz > > > > Harald, Dave: > > > > for peace of mind, can you please share the output of > > > > turbostat --interval 1 sleep 0 > > This is a Lenovo T410. > > turbostat version 20.03.20 - Len Brown > CPUID(0): GenuineIntel 0xb CPUID levels; 0x80000008 xlevels; family:model:stepping 0x6:25:5 (6:37:5) > [...] > cpu0: MSR_TURBO_RATIO_LIMIT: 0x00001416 > 20 * 133.3 = 2666.6 MHz max turbo 2 active cores > 22 * 133.3 = 2933.3 MHz max turbo 1 active cores 2 cores/ 4 threads, reported 4C turbo frequency of zero (i.e. bits 31:24 in MSR_TURBO_RATIO_LIMIT). This is consistent with all other occurrences of this bug that have been reported. Thanks Dave for your reply. Giovanni