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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C4CDC43334 for ; Tue, 14 Jun 2022 23:07:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358200AbiFNXHA (ORCPT ); Tue, 14 Jun 2022 19:07:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358411AbiFNXGq (ORCPT ); Tue, 14 Jun 2022 19:06:46 -0400 Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD8C55372A; Tue, 14 Jun 2022 16:06:40 -0700 (PDT) Received: by mail-pg1-x535.google.com with SMTP id f65so9816655pgc.7; Tue, 14 Jun 2022 16:06:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :references:from:in-reply-to:content-transfer-encoding; bh=42av7YccJZwfJfbLS94o0cmZvyb3OSKawVNa38bn1Nw=; b=QJdJD1/xomxo4MujjvIdxEpf8Yi6xAgTBdHfwKLfwLZ1YciE11z6yWkCw5+yuuJ0N+ TiOU97D2IuAKalPEI7q+rJR0SLmwqtQ8WAJOWwUzcHPXBz4k5nI+MF8V9HMtzEwjitbv I+aWIp0O/NtWPIei/Zv2f59PsTXRQRhjg3usiqgWsBZmOcsxp3xhfgQ+nVQ6zdyJlr1a rSgac4dz1E/Lodd4q0b8EAg2x2PMgO4L+BM2sMCOAOl8WvxhGkWMfd7+3tZIQWwTBAYR 1BqY0eiRnyVZbG2RjFXRNL/8O3Z+SPAERQoYPGTiULSrD+cJpVoWX/pfk7t0G5akV3Z4 xC8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:references:from:in-reply-to :content-transfer-encoding; bh=42av7YccJZwfJfbLS94o0cmZvyb3OSKawVNa38bn1Nw=; b=aRSJs93TbhivFNx/NbfbyxYooJoET4SR7+DehPMNUihqoGjfxncYqe6Bor8e572Ga3 am1KbrEhZbXVFTB9VBjzpEZCYDnZU9lSbYm3F4oDQtg6yojP/UeqivvcXNkbHlxH3IlD o5Tc/vDcswjfxn3C7/+9S4gGfhNZVcFDmUncWlh/Mjg7R6JavixQimcBk5qcNOIFjiTn tytdm3EezFGbecrpFBgT7vq+IqN9/tjgecktk8bylVSjR9mrUxhFjS16gk0bAm9M11B2 McYuJzo/yYUMLfQGwSyw9NP6hSQT8KIhfuYbeXmdNtyTw4uCRBsiK8hdhIrwzx5fh50Z StZg== X-Gm-Message-State: AOAM533fbmQQiXkxYanePTvelMRpk25lQBOAf3hnL2cmE9N2SJg+YlwO 86F64KoZprw6+EXmRCk1fMPKHzoBVTE= X-Google-Smtp-Source: ABdhPJzU5RacWF1n4c/IE6489r/hNvE5yfir9PjcH0+N2/H5ip/eJyEH42vwxVUUTjvNgmSlwHZUog== X-Received: by 2002:a63:2a47:0:b0:3fe:2437:5d25 with SMTP id q68-20020a632a47000000b003fe24375d25mr6580177pgq.539.1655248000184; Tue, 14 Jun 2022 16:06:40 -0700 (PDT) Received: from [172.30.1.37] ([14.32.163.5]) by smtp.gmail.com with ESMTPSA id n89-20020a17090a5ae200b001e880972840sm131881pji.29.2022.06.14.16.06.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Jun 2022 16:06:39 -0700 (PDT) Message-ID: <95e3a5ff-3f41-d7bf-fac5-2dbd2832f767@gmail.com> Date: Wed, 15 Jun 2022 08:06:36 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v3 3/5] PM / devfreq: Fix kernel panic with cpu based scaling to passive gov Content-Language: en-US To: Christian 'Ansuel' Marangi , MyungJoo Ham , Kyungmin Park , Chanwoo Choi , Sibi Sankar , Saravana Kannan , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220614110701.31240-1-ansuelsmth@gmail.com> <20220614110701.31240-4-ansuelsmth@gmail.com> From: Chanwoo Choi In-Reply-To: <20220614110701.31240-4-ansuelsmth@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22. 6. 14. 20:06, Christian 'Ansuel' Marangi wrote: > The cpufreq passive register notifier can PROBE_DEFER and the devfreq > struct is freed and then reallocaed on probe retry. > The current logic assume that the code can't PROBE_DEFER so the devfreq > struct in the this variable in devfreq_passive_data is assumed to be > (if already set) always correct. > This cause kernel panic as the code try to access the wrong address. > To correctly handle this, update the this variable in > devfreq_passive_data to the devfreq reallocated struct. > > Fixes: a03dacb0316f ("PM / devfreq: Add cpu based scaling support to passive governor") > Signed-off-by: Christian 'Ansuel' Marangi > --- > drivers/devfreq/governor_passive.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c > index 3c3322adea03..be8aa6830413 100644 > --- a/drivers/devfreq/governor_passive.c > +++ b/drivers/devfreq/governor_passive.c > @@ -395,8 +395,7 @@ static int devfreq_passive_event_handler(struct devfreq *devfreq, > if (!p_data) > return -EINVAL; > > - if (!p_data->this) > - p_data->this = devfreq; > + p_data->this = devfreq; > > switch (event) { > case DEVFREQ_GOV_START: Applied it to devfreq-fixes. Thanks. -- Best Regards, Samsung Electronics Chanwoo Choi