[PATCH linux dev-4.10] hwmon (occ): Fix integer overflow in multiplication
joel at jms.id.au
Tue Dec 19 01:11:25 AEDT 2017
On Sat, Dec 9, 2017 at 8:47 AM, Eddie James <eajames at linux.vnet.ibm.com> wrote:
> On 12/08/2017 12:16 AM, Joel Stanley wrote:
>> On Thu, Dec 7, 2017 at 5:49 AM, Eddie James <eajames at linux.vnet.ibm.com>
>>> --- a/drivers/hwmon/occ/common.c
>>> +++ b/drivers/hwmon/occ/common.c
>>> @@ -468,7 +468,7 @@ static ssize_t occ_show_power_1(struct device *dev,
>>> struct device_attribute *attr, char
>>> int rc;
>>> - u32 val = 0;
>>> + u64 val = 0;
>>> struct power_sensor_1 *power;
>>> struct occ *occ = dev_get_drvdata(dev);
>>> struct occ_sensors *sensors = &occ->sensors;
>>> @@ -491,11 +491,11 @@ static ssize_t occ_show_power_1(struct device *dev,
>>> val = get_unaligned_be32(&power->accumulator);
>>> case 3:
>>> - val = get_unaligned_be16(&power->value) * 1000000;
>>> + val = (u64)get_unaligned_be16(&power->value) *
>> I don't think these casts are required, are they?
> I'm not at all sure. I didn't think adding ULL was required here, but
> apparently it is. I don't really trust GCC...
Sorry, I thought you were joking here. GCC is behaving as it should.
Hit me up on IRC for an explanation sometime.
Can you resend without the casts?
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