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=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 67737C07E95 for ; Wed, 7 Jul 2021 16:36:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FA1A61CCC for ; Wed, 7 Jul 2021 16:36:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230349AbhGGQil (ORCPT ); Wed, 7 Jul 2021 12:38:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230110AbhGGQik (ORCPT ); Wed, 7 Jul 2021 12:38:40 -0400 Received: from mail-oi1-x22a.google.com (mail-oi1-x22a.google.com [IPv6:2607:f8b0:4864:20::22a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F180EC061762; Wed, 7 Jul 2021 09:35:58 -0700 (PDT) Received: by mail-oi1-x22a.google.com with SMTP id w127so4017367oig.12; Wed, 07 Jul 2021 09:35:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:to:cc:references:from:subject:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=SdjtKulK52JZbDskOxsiTOMKU9j9/kBAI8zRtWAf2MY=; b=CA8hoCCs18wpIptwPbG1ZM86QyNMU0CxtiAtNqwc3ByzH2geqToOZFz4TdwAd1lddQ OZctWgjCLRD+fV7WF7tg7zILckUHKn0Iy+kzh2sYyc8lEufKRTDQxdvjIyM13/BQ8bO9 dCCWS8q4SPWH6tZalY+wLqE+qEUaSiNuw0Pw7b9PeSgXXs+qROKoJ3vpGryNjf5j/yft CIjqiXApDJNq7UAJcWFqPQOokzWUFODcUYXjUN5zcYa40StcBT2+pxJ6m4M0+qqPuyQD gmb6WZ4RtRlMd++TqfA4AO+4YyAaEVRMd2GLT6W6vR0hGickXta1pIK8xS0Wnv+WgbfH SUug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:to:cc:references:from:subject:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=SdjtKulK52JZbDskOxsiTOMKU9j9/kBAI8zRtWAf2MY=; b=CrmlluYnDFpMfUkSMuaiXuMYt8vY1BRBgfFxwCW0HGaX8MK8bx95FaQWrlNpCAiSN0 PJ+/XsmlK/wfoRo6ATP1OO/upO3lgQBmnDEbQvz+tRPhg8IBOJQbykwPFsPPzitao+w1 9pnvYCtb71c6FavYnqJ6o+vYPNCkc4nr4iW5QqpgYYl+43pvKZI9lQLJhswX8EcqW3JV cg72t4TsfeUB85xuWiNeiSJPx3vRDmEgoa+Qbe37AHRgPTEx2j25oSvJFYwU5WARvNII LvyDSUMTqkwpwnauzkwtfKcIx1bCqY07y07xGX9MjYH9Av/1ZILyXt125HMdhqnFKMu/ odiA== X-Gm-Message-State: AOAM533lcOpxJAv7qVwB99CXSwO90lm+Y/0ay/UPsWUMKENpu6oFZsyk s5PoRxNk2AXiwbkAVhB69Ic= X-Google-Smtp-Source: ABdhPJypEzkEn+0VEkE7tglsHJvM/4SXWPXbZNsgiYzseXIpBJ6uElV7CRqGo/1VwBMa40vpUXMkTA== X-Received: by 2002:a54:4797:: with SMTP id o23mr8901907oic.158.1625675758396; Wed, 07 Jul 2021 09:35:58 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id d7sm4019679otb.66.2021.07.07.09.35.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Jul 2021 09:35:55 -0700 (PDT) Sender: Guenter Roeck To: Valentin Schneider , Alexey Kardashevskiy , Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, Ingo Molnar , Peter Zijlstra , x86@kernel.org References: <20210512094636.2958515-1-valentin.schneider@arm.com> <162081815405.29796.14574924529325899839.tip-bot2@tip-bot2> <20210706194456.GA1823793@roeck-us.net> <87fswr6lqv.mognet@arm.com> <20210707120305.GB115752@lothringen> <87czru727k.mognet@arm.com> <878s2i6uk2.mognet@arm.com> From: Guenter Roeck Subject: Re: [tip: sched/core] sched/core: Initialize the idle task with preemption disabled Message-ID: Date: Wed, 7 Jul 2021 09:35:51 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <878s2i6uk2.mognet@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/7/21 7:57 AM, Valentin Schneider wrote: > On 08/07/21 00:35, Alexey Kardashevskiy wrote: >> On 08/07/2021 00:14, Guenter Roeck wrote: >>> >>> Can you reproduce the problem with a powerpc qemu emulation ? >>> If so, how do you reproduce it there ? Reason for asking is that I don't >>> see >>> the problem with any of my powerpc emulations, and I would like to add test >>> case(s) if possible. >> >> I can reproduce the problem on powerpc easily - qemu with "-smp 2" does it. >> > > So on powerpc I'm chasing a slightly different problem, reported at > [1]. I couldn't get it to trigger on qemu for powerpc64, and I'm still > struggling with powerpc. Could you please share you qemu invocation & > kernel .config? Thanks. > I think I have it. pseries_defconfig, and pseries emulation, started with "-smp 2" and qemu-system-ppc64: [ 0.731644][ T1] smp: Bringing up secondary CPUs ...^M [ 0.750546][ T0] BUG: scheduling while atomic: swapper/1/0/0x00000000^M [ 0.752119][ T0] no locks held by swapper/1/0.^M [ 0.752309][ T0] Modules linked in:^M [ 0.752684][ T0] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.13.0-11855-g77d34a4683b0 #1^M [ 0.753197][ T0] Call Trace:^M [ 0.753334][ T0] [c000000008737b20] [c0000000009f9b18] .dump_stack_lvl+0xa4/0x100 (unreliable)^M [ 0.754224][ T0] [c000000008737bb0] [c000000000190ed0] .__schedule_bug+0xa0/0xe0^M [ 0.754459][ T0] [c000000008737c30] [c000000001182518] .__schedule+0xc08/0xd90^M [ 0.754738][ T0] [c000000008737d20] [c000000001182b8c] .schedule_idle+0x2c/0x60^M [ 0.754945][ T0] [c000000008737d90] [c0000000001a48ec] .do_idle+0x29c/0x3c0^M [ 0.755145][ T0] [c000000008737e60] [c0000000001a4df0] .cpu_startup_entry+0x30/0x40^M [ 0.755403][ T0] [c000000008737ee0] [c00000000005ef10] .start_secondary+0x2c0/0x300^M [ 0.755621][ T0] [c000000008737f90] [c00000000000d254] start_secondary_prolog+0x10/0x14^M [ 0.764164][ T1] smp: Brought up 1 node, 2 CPUs^M Guenter