hwmon: (asus_atk0110) fix uninitialized data access

commit a2125d02443e9a4e68bcfd9f8004fa23239e8329 upstream.

The latest gcc-7 snapshot adds a warning to point out that when
atk_read_value_old or atk_read_value_new fails, we copy
uninitialized data into sensor->cached_value:

drivers/hwmon/asus_atk0110.c: In function 'atk_input_show':
drivers/hwmon/asus_atk0110.c:651:26: error: 'value' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Adding an error check avoids this. All versions of the driver
are affected.

Fixes: 2c03d07ad54d ("hwmon: Add Asus ATK0110 support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/hwmon/asus_atk0110.c b/drivers/hwmon/asus_atk0110.c
index 83d2fbd..b2a0bad 100644 (file)
--- a/drivers/hwmon/asus_atk0110.c
+++ b/drivers/hwmon/asus_atk0110.c
@@ -645,6 +645,9 @@ static int atk_read_value(struct atk_sensor_data *sensor, u64 *value)
                else
                        err = atk_read_value_new(sensor, value);
 
                else
                        err = atk_read_value_new(sensor, value);
 

+               if (err)
+                       return err;
+

                sensor->is_valid = true;
                sensor->last_updated = jiffies;
                sensor->cached_value = *value;
                sensor->is_valid = true;
                sensor->last_updated = jiffies;
                sensor->cached_value = *value;