On 08/07/2017 11:56 PM, Pavan Kondeti wrote:
Hi Santosh,

On Mon, Aug 7, 2017 at 6:36 PM, Santosh Mardi <gsant...@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 <gsant...@codeaurora.org>
  drivers/devfreq/governor_userspace.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/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,
         data = devfreq->data;

-       sscanf(buf, "%lu", &wanted);
+       err = sscanf(buf, "%lu", &wanted);

Also, we could just use kstroul().

+       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;
         return err;


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