hwmon: (lm90) Prevent integer overflow/underflow in hysteresis calculations

Commit b50aa49638c7 ("hwmon: (lm90) Prevent integer underflows of
temperature calculations") addressed a number of underflow situations
when writing temperature limits. However, it missed one situation, seen
when an attempt is made to set the hysteresis value to MAX_LONG and the
critical temperature limit is negative.

Use clamp_val() when setting the hysteresis temperature to ensure that
the provided value can never overflow or underflow.

Fixes: b50aa49638c7 ("hwmon: (lm90) Prevent integer underflows of temperature calculations")
Cc: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index b05d73c4fbe2aad15d48e6eb5d426249d7b3725d..72969ea83d82e203bc50f2fca8a30acd468bc514 100644 (file)
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -1160,8 +1160,8 @@ static int lm90_set_temphyst(struct lm90_data *data, long val)
        else
                temp = temp_from_s8(data->temp8[LOCAL_CRIT]);
 
-       /* prevent integer underflow */
-       val = max(val, -128000l);
+       /* prevent integer overflow/underflow */
+       val = clamp_val(val, -128000l, 255000l);
 
        data->temp_hyst = hyst_to_reg(temp - val);
        err = i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,