Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.13 32/99] hwmon: (ntc_thermistor) Avoid math overflow | Date | Thu, 20 Feb 2014 15:52:27 -0800 |
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3.13-stable review patch. If anyone has any objections, please let me know.
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From: Doug Anderson <dianders@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 <dianders@chromium.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@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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