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authorDoug Anderson <dianders@chromium.org>2014-02-13 17:39:34 -0500
committerGuenter Roeck <linux@roeck-us.net>2014-02-13 22:43:52 -0500
commitd3d89c468ceebbcf9423d1a3d66c5bf91f569570 (patch)
tree857d835b47cdce23bfaa37ed81c4b96a3a5cd54d /drivers/hwmon
parentb28a960c42fcd9cfc987441fa6d1c1a471f0f9ed (diff)
hwmon: (ntc_thermistor) Avoid math overflow
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 <dianders@chromium.org> Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/ntc_thermistor.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c
index 8c23203915af..8a17f01e8672 100644
--- a/drivers/hwmon/ntc_thermistor.c
+++ b/drivers/hwmon/ntc_thermistor.c
@@ -145,7 +145,7 @@ struct ntc_data {
145static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) 145static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
146{ 146{
147 struct iio_channel *channel = pdata->chan; 147 struct iio_channel *channel = pdata->chan;
148 unsigned int result; 148 s64 result;
149 int val, ret; 149 int val, ret;
150 150
151 ret = iio_read_channel_raw(channel, &val); 151 ret = iio_read_channel_raw(channel, &val);
@@ -155,10 +155,10 @@ static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
155 } 155 }
156 156
157 /* unit: mV */ 157 /* unit: mV */
158 result = pdata->pullup_uv * val; 158 result = pdata->pullup_uv * (s64) val;
159 result >>= 12; 159 result >>= 12;
160 160
161 return result; 161 return (int)result;
162} 162}
163 163
164static const struct of_device_id ntc_match[] = { 164static const struct of_device_id ntc_match[] = {