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authorDoug Anderson <dianders@chromium.org>2014-02-13 14:39:34 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-22 12:41:27 -0800
commit600b64afd789d3d0deaf467b5fd88bca8d459768 (patch)
treebf85aa357aee31b0626877f277c203d75f70f1d0
parent5f32e4632c22a12b8ddc2e16c2be6b2988baf57a (diff)
downloadlinux-600b64afd789d3d0deaf467b5fd88bca8d459768.tar.gz
hwmon: (ntc_thermistor) Avoid math overflow
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 <dianders@chromium.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 d6d640a733d..9297164a23a 100644
--- 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_thermistor_platform_data *pdata)
}
/* 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[] = {