From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752100AbdHHG42 (ORCPT ); Tue, 8 Aug 2017 02:56:28 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:33238 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751880AbdHHG40 (ORCPT ); Tue, 8 Aug 2017 02:56:26 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org AC8C460250 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=pkondeti@codeaurora.org MIME-Version: 1.0 In-Reply-To: <1502111205-22560-2-git-send-email-gsantosh@codeaurora.org> References: <1502111205-22560-1-git-send-email-gsantosh@codeaurora.org> <1502111205-22560-2-git-send-email-gsantosh@codeaurora.org> From: Pavan Kondeti Date: Tue, 8 Aug 2017 12:26:24 +0530 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] devfreq: add error check for sscanf in userspace governor To: Santosh Mardi Cc: myungjoo.ham@samsung.com, kyungmin.park@samsung.com, rafael.j.wysocki@intel.com, cw00.choi@samsung.com, linux-pm@vger.kernel.org, LKML , gsantosh@qti.qualcomm.com, skannan@quicinc.com, rgottimu@qti.qualcomm.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Santosh, On Mon, Aug 7, 2017 at 6:36 PM, Santosh Mardi wrote: > store_freq function of devfreq userspace governor > executes further, even if error is returned from sscanf, > this will result in setting up wrong frequency value. > > Add proper error check to bail out if any error is returned. > > Signed-off-by: Santosh Mardi > --- > drivers/devfreq/governor_userspace.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c > index 77028c2..1d0c9cc 100644 > --- a/drivers/devfreq/governor_userspace.c > +++ b/drivers/devfreq/governor_userspace.c > @@ -53,12 +53,15 @@ static ssize_t store_freq(struct device *dev, struct device_attribute *attr, > mutex_lock(&devfreq->lock); > data = devfreq->data; > > - sscanf(buf, "%lu", &wanted); > + err = sscanf(buf, "%lu", &wanted); > + if (err != 1) > + goto out; You can save this goto statement by moving this sscanf checking to before taking the mutex. > data->user_frequency = wanted; > data->valid = true; > err = update_devfreq(devfreq); > if (err == 0) > err = count; > +out: > mutex_unlock(&devfreq->lock); > return err; > } > -- > 1.9.1 > -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project