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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 5B37DC433DF for ; Thu, 30 Jul 2020 08:22:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38572204EA for ; Thu, 30 Jul 2020 08:22:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="U9NLMWn2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729146AbgG3IWe (ORCPT ); Thu, 30 Jul 2020 04:22:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55040 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726194AbgG3IWc (ORCPT ); Thu, 30 Jul 2020 04:22:32 -0400 Received: from mail-ed1-x544.google.com (mail-ed1-x544.google.com [IPv6:2a00:1450:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 347EAC061794 for ; Thu, 30 Jul 2020 01:22:32 -0700 (PDT) Received: by mail-ed1-x544.google.com with SMTP id c15so9641061edj.3 for ; Thu, 30 Jul 2020 01:22:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=P5tO026HCWhunpPtUraf4hK8sVUtc5cHl/ZsmE/rYmg=; b=U9NLMWn24gZt8WtxgpL5aoU3QKrTkHkD6/dcKdC4LphBD4cX3BQGCLeuyfX+75BWAp oqmNE3yIYkcCRPpODyKk+EaQ2hBT+t0Qe4YmIMMEwbJn9lTonhzBwA/xe9xYTydOfYSK HA1PpxohUeLcNPINlNAKk4SvZ6hLfDaa9E0dhHIP4akiH8tF2bh3FZoRYtpRhp+Nx6UC 1PYaVfzDygnlZ1Uc9IkJRDKBXmM43Cfw8BMqnCjjpyeKIfSWZRV17ug4/S/amlstz+td 2VWsuOyw5uPhwFiREY/DqcBiUTXuo/N+Cyo5k7e2zuOQ+N/GH5dvcSOu28Foo4wY8B2w L0yw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=P5tO026HCWhunpPtUraf4hK8sVUtc5cHl/ZsmE/rYmg=; b=FM4w8zgvLJZe+6/LaMVrad9kcyEcKALQODoXQS5GZBN9YV/NDZaCRmoQGFaYqBY+XT kMj7yuXH/S5qBhJ2OdAhSpB53mTM/DdjUgSrjOCByis+bnmyq+c8zTosCdXNzmvCvzlk lEQB8G4fIm6zEMYsWxKNXwWKtBEUyZU7yKkxGbrTDmmTNuXwxzhntnSdB7CzIaoIKiYc TyElXT7eFOF+5J5xaZONM6n3AY/8i3JQNMHotUNrgo/FpfnhY3cE9QSL81kt9+XmLcZZ GgbCtZ9rzghfksityLP+8l0HkaFGbZ0YGuyczLFxFfrgzr/cX/CFHsCUXAPlfodPu23x 96Og== X-Gm-Message-State: AOAM5315AVhtNfsmG8ikhOWa7KGJXPYfhn7bKSa/utL4535sfeeo/pSG D60E8wHr2IDPxdeokQeyt8U= X-Google-Smtp-Source: ABdhPJz6I16zjQSU3JvaPfMdjbrDhwnziZ8PJqlqVpoGsGVBZPF4lHPfeb/btve/9CoadU16h9iMfg== X-Received: by 2002:a05:6402:13d0:: with SMTP id a16mr1491655edx.269.1596097350964; Thu, 30 Jul 2020 01:22:30 -0700 (PDT) Received: from skbuf ([188.26.57.97]) by smtp.gmail.com with ESMTPSA id b18sm4847551ejc.41.2020.07.30.01.22.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jul 2020 01:22:30 -0700 (PDT) Date: Thu, 30 Jul 2020 11:22:28 +0300 From: Vladimir Oltean To: Kurt Kanzenbach Cc: Alison Wang , catalin.marinas@arm.com, will@kernel.org, paulmck@kernel.org, mw@semihalf.com, leoyang.li@nxp.com, vladimir.oltean@nxp.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Anna-Maria Gleixner Subject: Re: [RFC PATCH] arm64: defconfig: Disable fine-grained task level IRQ time accounting Message-ID: <20200730082228.r24zgdeiofvwxijm@skbuf> References: <20200729033934.22349-1-alison.wang@nxp.com> <877dumbtoi.fsf@kurt> <20200729094943.lsmhsqlnl7rlnl6f@skbuf> <87mu3ho48v.fsf@kurt> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87mu3ho48v.fsf@kurt> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 30, 2020 at 09:23:44AM +0200, Kurt Kanzenbach wrote: > Hi Vladimir, > > On Wed Jul 29 2020, Vladimir Oltean wrote: > > For more context, here is my original report of the issue: > > https://lkml.org/lkml/2020/6/4/1062 > > > > Just like you, I could not reproduce the RCU stalls and system hang on a > > 5.6-rt kernel, just on mainline and derivatives, using the plain > > defconfig. > > > > The issue is not specific to Layerscape or i.MX8, but rather I was able > > to see the same behavior on Marvell Armada 37xx as well as Qualcomm > > MSM8976. > > > > So, while of course I agree that disabling IRQ time accounting for arm64 > > isn't a real solution, it isn't by far an exaggerated proposal either. > > Nonetheless, the patch is just a RFC and should be treated as such. We > > are at a loss when it comes to debugging this any further and we would > > appreciate some pointers. > > Yeah, sure. I'll try to reproduce this issue first. So it triggers with: > > * arm64 > * mainline, not -rt kernel > * opened serial console > * irq accounting enabled > > Anything else? > > Thanks, > Kurt Thanks for giving a helping hand, Kurt. The defconfig should be enough. In the interest of full disclosure, the only arm64 device on which we didn't reproduce this was the 16-core LX2160A. But we did reproduce on that with maxcpus=1 though. And also on msm8976 with all 8 cores booted. Just mentioning this in case you're testing on a 16-core system, you might want to reduce the number a bit. Thanks, -Vladimir