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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 BC586C43603 for ; Thu, 5 Dec 2019 11:00:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8AA1824648 for ; Thu, 5 Dec 2019 11:00:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="O5H8Njm4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729048AbfLELAi (ORCPT ); Thu, 5 Dec 2019 06:00:38 -0500 Received: from mail-pf1-f177.google.com ([209.85.210.177]:37831 "EHLO mail-pf1-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729041AbfLELAh (ORCPT ); Thu, 5 Dec 2019 06:00:37 -0500 Received: by mail-pf1-f177.google.com with SMTP id s18so1454222pfm.4 for ; Thu, 05 Dec 2019 03:00:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ZUGsVDU+ezq7myFy16KsH7Hg/PU1W1LYB5g4ks2ehVc=; b=O5H8Njm452u9OKbM8vjO4aaKIC1eEMsZ/1jHUU2NhRgNVZWcIR7noDrSLQw46QVO+W HFt1ak/3W73lZPCgkCs0UcFyP+A6A8FeKtUWB5gX2skS45yrOEEZj4SyjPyGqkOckPyc t05kP41FAPGj+FRsGxj+b5WEczTA+Ftp4/tTw0A2M/3SELPXp3DHoP7e8DeMl4fvHvN8 p9VIb/f5dF1iBnagjO0i3cLD0QGH5DTBVp1AN3SyEM5Z+utkHOsZPaMEskc9EWXzzPIA RIZ9wQvidk6TYW2zuoig7hAEeX2OcCxyb0H66nQk4x0nBIpsXj5KSS2EHuwC7/VLL8a1 qB+A== 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:user-agent; bh=ZUGsVDU+ezq7myFy16KsH7Hg/PU1W1LYB5g4ks2ehVc=; b=qHpucn9zbJLubgBaUcQYpasKPElAIyMMofCZhFz4jENj4DzQa/7kaIqBmNuymWr1pz ZAW7j9MULrZqWg9kbrV14KY4SCXeoLOgq+QtjIv0nhhO+YO1pkomToI7JFtzRFrQzKdS VeDlZdw3HbRGpNtyQwJMhU7AcSqDEt49aJPW07g9jqNG5hSUSDyzUNufGnuj73bgZN6C m0l7be5kcPcNJi5ww6++R1DG/0XqXv3uZYbrMMH5aWumTbf8/afiL51T2eMe4j91l36L tio+DYEHbOPjYu1TQtxsf2ts+x55+VarBemUB+4u72Rl2MrtZ0+fxMk277CRnKa6DwDW EBwA== X-Gm-Message-State: APjAAAU5o710AHtKB+PjR2MFFCyw9IokLDWBr5UJfxdUlzcfh1NXUBPw KNDLMxXpxFiIWHBoUi3gedAS1g== X-Google-Smtp-Source: APXvYqxatt6HrAhL36xb4JGDXE+letcEmBUCLi2FEhJFSTk2NZryP1pAyF95hJUirNfRa0GAMyl+sw== X-Received: by 2002:a63:e009:: with SMTP id e9mr8814145pgh.222.1575543636912; Thu, 05 Dec 2019 03:00:36 -0800 (PST) Received: from localhost ([122.171.112.123]) by smtp.gmail.com with ESMTPSA id c68sm12333354pfc.156.2019.12.05.03.00.35 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 05 Dec 2019 03:00:36 -0800 (PST) Date: Thu, 5 Dec 2019 16:30:34 +0530 From: Viresh Kumar To: Anson Huang Cc: "Rafael J. Wysocki" , Jacky Bai , "linux-pm@vger.kernel.org" Subject: Re: About CPU hot-plug stress test failed in cpufreq driver Message-ID: <20191205110034.gbnlnqggmk2hb44z@vireshk-i7> References: <7507929.7xP3Io3WO9@kreacher> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716-391-311a52 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On 05-12-19, 08:53, Anson Huang wrote: > Hi, Rafael > This issue is very weird, the irq_work used in cpufreq_governor.c is very simple, ONLY one entry to claim the irq_work, and cpufreq_governor's irq_work is a private irq_work structure, no other drivers use it. I added some trace event in cpufreq_governor.c and irq_work.c, every time, the issue happened at the point of CPU1/2/3 all off, and CPU1 start ON line, but when CPU1 tried to sync the irq_work in cpufreq_dbs_governor_stop(), the irq_work shows that previous work is pending on CPU3 which is offline, I also had the trace event in irq_work_claim(), but no any log shows the cpufreq_governor irq_work is claimed on CPU3 after CPU3 offline, below is the debug patch I added and the log on 2 consoles: > If I understand it correctly, the irq work used in cpufreq_governor ONLY has one entry of calling irq_work_queue() which will be ONLY claimed on the CPU calling the irq_work_queue(), but from trace result, I have NOT see where CPU3 could call irq_work_queue() after it finishes the irq work sync before offline. Could it something wrong related to cache maintain during CPU hotplug? I think you earlier said that the issue wasn't there in 4.19 kernel, right ? What about doing git bisect to see if we can find the offending commit ? -- viresh