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SubjectRe: [PATCH] devfreq: add error check for sscanf in userspace governor
Hi,

On 2017년 08월 07일 22:06, 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 <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;
> data->user_frequency = wanted;
> data->valid = true;
> err = update_devfreq(devfreq);
> if (err == 0)
> err = count;
> +out:
> mutex_unlock(&devfreq->lock);
> return err;
> }
>

Looks good to me.
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

--
Best Regards,
Chanwoo Choi
Samsung Electronics

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