3.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Doug Anderson <diand...@chromium.org>

commit d3d89c468ceebbcf9423d1a3d66c5bf91f569570 upstream.

The ntc thermistor code was doing math whose temporary result might
have overflowed 32-bits.  We need some casts in there to make it safe.

In one example I found:
- pullup_uV: 1800000
- result of iio_read_channel_raw: 3226
- 1800000 * 3226 => 0x15a1cbc80

Signed-off-by: Doug Anderson <diand...@chromium.org>
Signed-off-by: Guenter Roeck <li...@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/hwmon/ntc_thermistor.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/hwmon/ntc_thermistor.c
+++ b/drivers/hwmon/ntc_thermistor.c
@@ -145,7 +145,7 @@ struct ntc_data {
 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
 {
        struct iio_channel *channel = pdata->chan;
-       unsigned int result;
+       s64 result;
        int val, ret;
 
        ret = iio_read_channel_raw(channel, &val);
@@ -155,10 +155,10 @@ static int ntc_adc_iio_read(struct ntc_t
        }
 
        /* unit: mV */
-       result = pdata->pullup_uv * val;
+       result = pdata->pullup_uv * (s64) val;
        result >>= 12;
 
-       return result;
+       return (int)result;
 }
 
 static const struct of_device_id ntc_match[] = {


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