From patchwork Fri May 13 11:08:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Schspa Shi X-Patchwork-Id: 574143 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 D7DBDC433EF for ; Fri, 13 May 2022 11:09:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245323AbiEMLJD (ORCPT ); Fri, 13 May 2022 07:09:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379766AbiEMLJC (ORCPT ); Fri, 13 May 2022 07:09:02 -0400 Received: from mail-qt1-x832.google.com (mail-qt1-x832.google.com [IPv6:2607:f8b0:4864:20::832]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99BA71356A7; Fri, 13 May 2022 04:09:01 -0700 (PDT) Received: by mail-qt1-x832.google.com with SMTP id p4so6494936qtq.12; Fri, 13 May 2022 04:09:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=WmgMp6GvUkzNH+zUibeCMplxNIPkAGROCIcy5eW+4vc=; b=N2AbmWKlTMtelPKNo0GzQElQkZxny2h3l07Q4c8QSoeEwWdaGMyY7WZZMdWLyz4WVT NCj6+gULWAVEkyUOrerghm9J4y/JDVNh6isrScn4ctu4NaimjJFToPZgdVyEo9G2sBeY FpZvnTabZCoy9eZ7rDSd2q63+C/JPgqoffdK+lRxHGOKJUSxxLG80EsTUjkR43zbnjYf Jl+Fml9F6FSA9v3y6AgPQ9zLBqfBCUtZElkaXNydIOWkKpA0n7PI0qs5xxFCugxymM7W WVQ8WaDnqxmDDAE+K0wEclNqGBDxgvloaJ/dXb1iLk8s+HWBMmfmiboz/dhjizMT+aQb byXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=WmgMp6GvUkzNH+zUibeCMplxNIPkAGROCIcy5eW+4vc=; b=5L3YSt0STtXel7ulqDWEcfVk/FYXR7faCOj42LI/w4ZvVmGdz5flgy3Oz6T53QA6Hp imQJWXdEjdz81cpdOGlIaeVOsC0ShU17LX7n0sACvIz7PQ3mrfpHvHLOy2IvZL6iwG/L NCTE8Be5uGzP8pXC02WB0sxXUOaHPeGePujd/9JHhWP8Mw1lvizTEWwmrzu7nHfiqBO6 88gr6uHdESG7vmy1tYBhkKqefPfYlwY+d8x42m4nTNUN2V7uR4QX0n+8BltWTdkfK0Ek OWiucT+Ew2dAthYSF3uMwOs4+Lfzm4aMdasYI/v3Zqs+DrSA/L8C7r+xXod5g1jxJTSc SSXg== X-Gm-Message-State: AOAM533xY37AMXLMHG1nvLjCXH/xERYOXBaWzVRnVuciC/0/VVLKi3Pw TmYJ4dMUP5f5hidoVtXdEXt5HRHi7RQHRgUy X-Google-Smtp-Source: ABdhPJwNGzvFRR5or8n6Km5CQIiApH6yHBiP1d5j6g24mm+kstLp8O5NCyccJ9jSReCuCLlxPzCDcg== X-Received: by 2002:a05:622a:1e12:b0:2f3:d254:45b7 with SMTP id br18-20020a05622a1e1200b002f3d25445b7mr3995083qtb.88.1652440140560; Fri, 13 May 2022 04:09:00 -0700 (PDT) Received: from MBP.hobot.cc (ec2-13-59-0-164.us-east-2.compute.amazonaws.com. [13.59.0.164]) by smtp.gmail.com with ESMTPSA id b16-20020a05620a04f000b0069fd57d435fsm1127548qkh.101.2022.05.13.04.08.57 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 May 2022 04:08:59 -0700 (PDT) From: Schspa Shi To: rafael@kernel.org, viresh.kumar@linaro.org Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, schspa@gmail.com Subject: [PATCH v5 1/2] cpufreq: Abort show/store for half initialized policy Date: Fri, 13 May 2022 19:08:47 +0800 Message-Id: <20220513110848.20204-1-schspa@gmail.com> X-Mailer: git-send-email 2.29.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org If policy initialization fails after the sysfs files are created, there is a possibility that we may end up running show()/store() callbacks for half initialized policies, which may have unpredictable outcomes. Abort show/store in such a case by making sure the policy is active. Also inactivate the policy on such failures. Signed-off-by: Schspa Shi --- Changelog: v1 -> v2: - Fix bad critical region enlarge which causes uninitialized unlock. - Move cpumask_clear(policy->cpus); before out_offline_policy v2 -> v3: - Remove the missed down_write() before cpumask_and(policy->cpus, policy->cpus, cpu_online_mask); v3 -> v4: - Seprate to two patchs. - Add policy_is_inactive check before sysfs access v4 -> v5: - Change the commit message as Viresh advised. - Initialize ret to -EBUSY to get rid of the else part. --- drivers/cpufreq/cpufreq.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 80f535cc8a75..ba73be6f0490 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -947,13 +947,14 @@ static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) { struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); - ssize_t ret; + ssize_t ret = -EBUSY; if (!fattr->show) return -EIO; down_read(&policy->rwsem); - ret = fattr->show(policy, buf); + if (likely(!policy_is_inactive(policy))) + ret = fattr->show(policy, buf); up_read(&policy->rwsem); return ret; @@ -964,7 +965,7 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, { struct cpufreq_policy *policy = to_policy(kobj); struct freq_attr *fattr = to_attr(attr); - ssize_t ret = -EINVAL; + ssize_t ret = -EBUSY; if (!fattr->store) return -EIO; @@ -978,7 +979,8 @@ static ssize_t store(struct kobject *kobj, struct attribute *attr, if (cpu_online(policy->cpu)) { down_write(&policy->rwsem); - ret = fattr->store(policy, buf, count); + if (likely(!policy_is_inactive(policy))) + ret = fattr->store(policy, buf, count); up_write(&policy->rwsem); } @@ -1533,6 +1535,7 @@ static int cpufreq_online(unsigned int cpu) for_each_cpu(j, policy->real_cpus) remove_cpu_dev_symlink(policy, get_cpu_device(j)); + cpumask_clear(policy->cpus); up_write(&policy->rwsem); out_offline_policy: From patchwork Fri May 13 11:08:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Schspa Shi X-Patchwork-Id: 572463 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 D1B56C433F5 for ; Fri, 13 May 2022 11:09:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379775AbiEMLJL (ORCPT ); Fri, 13 May 2022 07:09:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39076 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1379766AbiEMLJI (ORCPT ); Fri, 13 May 2022 07:09:08 -0400 Received: from mail-qt1-x836.google.com (mail-qt1-x836.google.com [IPv6:2607:f8b0:4864:20::836]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7544F26C4DE; Fri, 13 May 2022 04:09:07 -0700 (PDT) Received: by mail-qt1-x836.google.com with SMTP id h3so6547255qtn.4; Fri, 13 May 2022 04:09:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7D8erwxOxrNwpL4kTMFZcWrJ5A/nWK5FWS+W1RtdNck=; b=PrYGICVhGTuengtryu36R642ZDAMVMtPk+eeETtYf2Cmfiw7mG7AGNsDQziNNnoIjo kh0QePFTODZMi99cysCpYNZIPSYqjFjyeNSwfgMtlVQZlXs3kVYlyF64y+jhDP5uO/XU XN95A7caOX4ZFmvvQasyvYYnVuvprWRvdPhVyBSWb5h/Kx6N+MJc4MKeGrt5QJbnRbK5 gHrKUl9rvVPpqkxUDK3PmpXXz7Vxd5rd/4HBlT/2rmGYRxGMx+18ohxiFLx/ptQ5eLK9 Y3c3QOgxsLZ7+GvAHHVPAfQFyjK5f/MrdTOxcDTQDs5fs0rCq1mmRReqDQ8F06orNO+9 V/3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=7D8erwxOxrNwpL4kTMFZcWrJ5A/nWK5FWS+W1RtdNck=; b=nxxV0+E3PETpsc2VbU5Yxfse/hObaEGumQFdp5rpa5F7qr8wQAd8gUeWlbYwNEDBDX TjshREhw6QyMt/9XxSpY35PVEpJapAxbBhufb/SyaGC1AjH0B+J0LqEPzfL2+Nmm9YET t0VnmRn/p5XXIT+nuE5uD7fFEon7l8gRAV3Fo8FOT9fiIiWVstmef5Kjck0wFwlV6UHs KGMWu1GlEiqygcevnJ7ONJUBDFN072CkP1g7AzUVUh6Mjc5zzi7UI/bHoK4seYWxrac1 XBVrD1cxhCIr6FxhMz3tM78VBTW72LWgnrToDh1/N8CSvyDj6XTzT3MIbo83q0Wp8jPf aaiw== X-Gm-Message-State: AOAM532Lbxzv2m4sOSwMTEk+w7fIqkGzbpbyhEtSVTedE9b7I0Xgcoob eYOPnBykOHPm89ZUxKaFBlqM4LmGcdv6p/BK X-Google-Smtp-Source: ABdhPJwCPd/MZyxOTX9dBYJL13str88G6bqD0TbvkdvtpdFYPqLm6Tda1ye9Cbbcr5wt9hwqcIQjNw== X-Received: by 2002:a05:622a:14c7:b0:2f3:d2ee:a676 with SMTP id u7-20020a05622a14c700b002f3d2eea676mr3926585qtx.604.1652440146548; Fri, 13 May 2022 04:09:06 -0700 (PDT) Received: from MBP.hobot.cc (ec2-13-59-0-164.us-east-2.compute.amazonaws.com. [13.59.0.164]) by smtp.gmail.com with ESMTPSA id b16-20020a05620a04f000b0069fd57d435fsm1127548qkh.101.2022.05.13.04.09.03 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 May 2022 04:09:06 -0700 (PDT) From: Schspa Shi To: rafael@kernel.org, viresh.kumar@linaro.org Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, schspa@gmail.com Subject: [PATCH v5 2/2] cpufreq: make interface functions and lock holding state clear Date: Fri, 13 May 2022 19:08:48 +0800 Message-Id: <20220513110848.20204-2-schspa@gmail.com> X-Mailer: git-send-email 2.29.0 In-Reply-To: <20220513110848.20204-1-schspa@gmail.com> References: <20220513110848.20204-1-schspa@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org cpufreq_offline() calls offline() and exit() under the policy rwsem But they are called outside the rwsem in cpufreq_online(). This patch move the offline(), exit(), online(), init() to be inside of policy rwsem to achieve a clear lock relationship. All the init() online() implement only initialize policy object without holding this lock and won't call cpufreq APIs need to hold this lock. Signed-off-by: Schspa Shi --- drivers/cpufreq/cpufreq.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index ba73be6f0490..0f0f202f9a05 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1339,12 +1339,12 @@ static int cpufreq_online(unsigned int cpu) down_write(&policy->rwsem); policy->cpu = cpu; policy->governor = NULL; - up_write(&policy->rwsem); } else { new_policy = true; policy = cpufreq_policy_alloc(cpu); if (!policy) return -ENOMEM; + down_write(&policy->rwsem); } if (!new_policy && cpufreq_driver->online) { @@ -1384,7 +1384,6 @@ static int cpufreq_online(unsigned int cpu) cpumask_copy(policy->related_cpus, policy->cpus); } - down_write(&policy->rwsem); /* * affected cpus must always be the one, which are online. We aren't * managing offline cpus here. @@ -1536,7 +1535,6 @@ static int cpufreq_online(unsigned int cpu) remove_cpu_dev_symlink(policy, get_cpu_device(j)); cpumask_clear(policy->cpus); - up_write(&policy->rwsem); out_offline_policy: if (cpufreq_driver->offline) @@ -1545,6 +1543,7 @@ static int cpufreq_online(unsigned int cpu) out_exit_policy: if (cpufreq_driver->exit) cpufreq_driver->exit(policy); + up_write(&policy->rwsem); out_free_policy: cpufreq_policy_free(policy);