From patchwork Fri Feb 1 06:15:45 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh Kumar X-Patchwork-Id: 10791841 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 147DA14E1 for ; Fri, 1 Feb 2019 06:16:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 06A97312A9 for ; Fri, 1 Feb 2019 06:16:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EE15D312C4; Fri, 1 Feb 2019 06:16:08 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4BF0C312A9 for ; Fri, 1 Feb 2019 06:16:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726659AbfBAGQA (ORCPT ); Fri, 1 Feb 2019 01:16:00 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:43609 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726467AbfBAGQA (ORCPT ); Fri, 1 Feb 2019 01:16:00 -0500 Received: by mail-pl1-f194.google.com with SMTP id gn14so2655690plb.10 for ; Thu, 31 Jan 2019 22:16:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=OWAwfc5wYY5PtG8pBPOfVRPrY8t3iMD9QATzlWF/GMo=; b=bYqqeHxuhWXUZATJfWLOrNfmFCQW9gujoTXIX3aKUkbBC8WV6YN4mlX4cZhFQdpzCf g/i7uoJlUX/RLzMm8/vxCsf0aX8RzFAHLjIeQ2GP0Q76iXL8vgmgbFPwALiCHMTBWcw8 TIPdjkwdI8oG6Gg67BMLF7X+2Qkv6AY/gHjQM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=OWAwfc5wYY5PtG8pBPOfVRPrY8t3iMD9QATzlWF/GMo=; b=L8EQgTj8IuWSi5KkNZNyAdRl7VY27X3VMh5wB/Sx2hO38+jZd1BtbddsYKYcoXNc6C IipAe04u+SRns8QyIUkxgWfXW0wuUsen0UvmZwiu/7kz6Hbt2BWAJOngRuWP/5gRWAP5 S6IPDnTS8vEUyeeac4uBzlrxf2svTzdu8sRp1hNynQjw6Vlx6DhU/QI/kd9+F4XGD70M qK+RsSvofW7udhl1QaCs5eGnk3BFAIu82aHKUZ18C56qsN7nJBmTEBXCkoxnWLBNGf9f 71G6TXN1+9QJjIV6wLXO2fwHEM+vXFAOVmUW2MPkdEle6ci4SIrEyVJldmA8wckotjXH yeCA== X-Gm-Message-State: AJcUukeZZqKT7XNWLiGQv2+upFHfxrOP5vdY3aNYuWwggR4sTZRTPe44 v8B8nno/u6sPPNCC1nh3j/9Ykw== X-Google-Smtp-Source: ALg8bN5tliiYj16YVnP7/Bof7v4XupPN8vWp6CW/mRpZ6U/Fly30woq1yIFK9vRbGiEWgpqY8sx7Eg== X-Received: by 2002:a17:902:7791:: with SMTP id o17mr37608663pll.60.1549001759710; Thu, 31 Jan 2019 22:15:59 -0800 (PST) Received: from localhost ([122.172.102.63]) by smtp.gmail.com with ESMTPSA id o4sm10080341pgs.12.2019.01.31.22.15.58 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Jan 2019 22:15:58 -0800 (PST) From: Viresh Kumar To: Rafael Wysocki Cc: Viresh Kumar , linux-pm@vger.kernel.org, Vincent Guittot , linux-kernel@vger.kernel.org Subject: [PATCH 2/2] cpufreq: stats: Fix concurrency issues while resetting stats Date: Fri, 1 Feb 2019 11:45:45 +0530 Message-Id: <927dcc1de6acad3dd2cfae4e300e6fee4f665101.1549001732.git.viresh.kumar@linaro.org> X-Mailer: git-send-email 2.20.1.321.g9e740568ce00 In-Reply-To: References: MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It is possible for cpufreq_stats_clear_table() and cpufreq_stats_record_transition() to get called concurrently and they will try to update same variables simultaneously and may lead to corruption of data. Prevent that with the help of existing spinlock. Signed-off-by: Viresh Kumar Reviewed-by: Matthias Kaehlcke --- drivers/cpufreq/cpufreq_stats.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c index 941e63e3e652..e2db5581489a 100644 --- a/drivers/cpufreq/cpufreq_stats.c +++ b/drivers/cpufreq/cpufreq_stats.c @@ -31,20 +31,20 @@ static void cpufreq_stats_update(struct cpufreq_stats *stats) { unsigned long long cur_time = get_jiffies_64(); - spin_lock(&cpufreq_stats_lock); stats->time_in_state[stats->last_index] += cur_time - stats->last_time; stats->last_time = cur_time; - spin_unlock(&cpufreq_stats_lock); } static void cpufreq_stats_clear_table(struct cpufreq_stats *stats) { unsigned int count = stats->max_state; + spin_lock(&cpufreq_stats_lock); memset(stats->time_in_state, 0, count * sizeof(u64)); memset(stats->trans_table, 0, count * count * sizeof(int)); stats->last_time = get_jiffies_64(); stats->total_trans = 0; + spin_unlock(&cpufreq_stats_lock); } static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf) @@ -62,7 +62,10 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf) if (policy->fast_switch_enabled) return 0; + spin_lock(&cpufreq_stats_lock); cpufreq_stats_update(stats); + spin_unlock(&cpufreq_stats_lock); + for (i = 0; i < stats->state_num; i++) { len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i], (unsigned long long) @@ -239,9 +242,11 @@ void cpufreq_stats_record_transition(struct cpufreq_policy *policy, if (old_index == -1 || new_index == -1 || old_index == new_index) return; + spin_lock(&cpufreq_stats_lock); cpufreq_stats_update(stats); stats->last_index = new_index; stats->trans_table[old_index * stats->max_state + new_index]++; stats->total_trans++; + spin_unlock(&cpufreq_stats_lock); }