From patchwork Mon Feb 24 07:15:00 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Saravana Kannan X-Patchwork-Id: 3706701 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id EE1B79F2F7 for ; Mon, 24 Feb 2014 07:15:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2EB962018E for ; Mon, 24 Feb 2014 07:15:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4EB5A2015A for ; Mon, 24 Feb 2014 07:15:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752286AbaBXHPQ (ORCPT ); Mon, 24 Feb 2014 02:15:16 -0500 Received: from smtp.codeaurora.org ([198.145.11.231]:57405 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752256AbaBXHPM (ORCPT ); Mon, 24 Feb 2014 02:15:12 -0500 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id D665C13EC94; Mon, 24 Feb 2014 07:15:12 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 486) id C825013EF4A; Mon, 24 Feb 2014 07:15:12 +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 38B5C13EC94; Mon, 24 Feb 2014 07:15:12 +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: Fix out of bounds access of transition table array Date: Sun, 23 Feb 2014 23:15:00 -0800 Message-Id: <1393226100-18428-1-git-send-email-skannan@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 X-Virus-Scanned: ClamAV using ClamSMTP 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 The previous_freq value for a device could be an invalid frequency that results in a error value being returned from devfreq_get_freq_level(). Check for an error value before using that to index into the transition table. Not doing this check will result in memory corruption when previous_freq is not a valid frequency. Signed-off-by: Saravana Kannan --- drivers/devfreq/devfreq.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index a0b2f7e..f91ea29 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -101,14 +101,20 @@ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) cur_time = jiffies; devfreq->time_in_state[lev] += cur_time - devfreq->last_stat_updated; - if (freq != devfreq->previous_freq) { - prev_lev = devfreq_get_freq_level(devfreq, - devfreq->previous_freq); + devfreq->last_stat_updated = cur_time; + + if (freq == devfreq->previous_freq) + return 0; + + prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); + if (prev_lev < 0) + return 0; + + 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; }