From: Pavan Kondeti <pkondeti@codeaurora.org>
To: Santosh Mardi <gsantosh@codeaurora.org>
Cc: myungjoo.ham@samsung.com, kyungmin.park@samsung.com,
rafael.j.wysocki@intel.com, cw00.choi@samsung.com,
linux-pm@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
gsantosh@qti.qualcomm.com, skannan@quicinc.com,
rgottimu@qti.qualcomm.com
Subject: Re: [PATCH] devfreq: add error check for sscanf in userspace governor
Date: Tue, 8 Aug 2017 12:26:24 +0530 [thread overview]
Message-ID: <CAEU1=PmSq+UXO_zwrMSTbsejUi5G8BCKaqYA_cxmo4pcFO1z_Q@mail.gmail.com> (raw)
In-Reply-To: <1502111205-22560-2-git-send-email-gsantosh@codeaurora.org>
Hi Santosh,
On Mon, Aug 7, 2017 at 6:36 PM, Santosh Mardi <gsantosh@codeaurora.org> 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 <gsantosh@codeaurora.org>
> ---
> 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
next prev parent reply other threads:[~2017-08-08 6:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-07 13:06 [PATCH] devfreq: add error check for sscanf in userspace governor Santosh Mardi
2017-08-07 13:06 ` Santosh Mardi
2017-08-08 0:51 ` Chanwoo Choi
2017-08-08 6:56 ` Pavan Kondeti [this message]
2017-08-08 19:26 ` Saravana Kannan
[not found] ` <CGME20170807130735epcas5p4386af2ade3bd98b67fc5a9c956152c7d@epcms1p5>
2017-08-08 0:14 ` MyungJoo Ham
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