From patchwork Fri Feb 28 03:38:57 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saravana Kannan X-Patchwork-Id: 3738141 Return-Path: X-Original-To: patchwork-linux-arm-msm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id DFF63BF13A for ; Fri, 28 Feb 2014 03:39:11 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0BD7F20259 for ; Fri, 28 Feb 2014 03:39:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2E1920255 for ; Fri, 28 Feb 2014 03:39:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750957AbaB1DjI (ORCPT ); Thu, 27 Feb 2014 22:39:08 -0500 Received: from smtp.codeaurora.org ([198.145.11.231]:42096 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818AbaB1DjH (ORCPT ); Thu, 27 Feb 2014 22:39:07 -0500 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 1644813EF1E; Fri, 28 Feb 2014 03:39:07 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 486) id 07F9D13EF83; Fri, 28 Feb 2014 03:39:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from skannan1-linux.qualcomm.com (i-global252.qualcomm.com [199.106.103.252]) (using TLSv1.1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: skannan@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 5DC8D13EF1E; Fri, 28 Feb 2014 03:39:06 +0000 (UTC) From: Saravana Kannan To: MyungJoo Ham , Kyungmin Park Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "Saravana Kannan" Subject: [PATCH] PM / devfreq: Rewrite devfreq_update_status() to fix multiple bugs Date: Thu, 27 Feb 2014 19:38:57 -0800 Message-Id: <1393558737-24037-1-git-send-email-skannan@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The current devfreq_update_status() has the following bugs: - If previous frequency doesn't have a valid level, it does an out of bounds access into the trans_table and causes memory corruption. - When the new frequency doesn't have a valid level, the time spent in the new frequency is counted towards the next valid frequency switch instead of being ignored. - The time spent on the previous frequency is added to the new frequency's stats instead of the previous frequency's stats. This patch fixes all of this. Signed-off-by: Saravana Kannan --- drivers/devfreq/devfreq.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index a0b2f7e..2042ec3 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -91,26 +91,35 @@ static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq) */ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) { - int lev, prev_lev; + int lev, prev_lev, ret = 0; unsigned long cur_time; - lev = devfreq_get_freq_level(devfreq, freq); - if (lev < 0) - return lev; - cur_time = jiffies; - devfreq->time_in_state[lev] += + + prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); + if (prev_lev < 0) { + ret = prev_lev; + goto out; + } + + devfreq->time_in_state[prev_lev] += cur_time - devfreq->last_stat_updated; - if (freq != devfreq->previous_freq) { - prev_lev = devfreq_get_freq_level(devfreq, - devfreq->previous_freq); + + lev = devfreq_get_freq_level(devfreq, freq); + if (lev < 0) { + ret = lev; + goto out; + } + + if (lev != prev_lev) { devfreq->trans_table[(prev_lev * devfreq->profile->max_state) + lev]++; devfreq->total_trans++; } - devfreq->last_stat_updated = cur_time; - return 0; +out: + devfreq->last_stat_updated = cur_time; + return ret; } /**