On 10/29/2014 01:43 AM, Dmitry Torokhov wrote:
> Expression haptic->pwm_dev->period * haptic->magnitude is of type 'unsigned
> int' and may overflow. We need to convert one of the operands to u64 before
> multiplying, instead of casting result (potentially overflown) to u64.
>
> Reported by Coverity: CID 1248753
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> ---
> drivers/input/misc/max77693-haptic.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/input/misc/max77693-haptic.c b/drivers/input/misc/max77693-haptic.c
> index 7b1fde9..ef6a9d6 100644
> --- a/drivers/input/misc/max77693-haptic.c
> +++ b/drivers/input/misc/max77693-haptic.c
> @@ -194,7 +194,7 @@ static int max77693_haptic_play_effect(struct input_dev *dev, void *data,
> struct ff_effect *effect)
> {
> struct max77693_haptic *haptic = input_get_drvdata(dev);
> - uint64_t period_mag_multi;
> + u64 period_mag_multi;
>
> haptic->magnitude = effect->u.rumble.strong_magnitude;
> if (!haptic->magnitude)
> @@ -205,8 +205,7 @@ static int max77693_haptic_play_effect(struct input_dev *dev, void *data,
> * The formula to convert magnitude to pwm_duty as follows:
> * - pwm_duty = (magnitude * pwm_period) / MAX_MAGNITUDE(0xFFFF)
> */
> - period_mag_multi = (int64_t)(haptic->pwm_dev->period *
> - haptic->magnitude);
> + period_mag_multi = (u64)haptic->pwm_dev->period * haptic->magnitude;
> haptic->pwm_duty = (unsigned int)(period_mag_multi >>
> MAX_MAGNITUDE_SHIFT);
>
>
Looks good to me.
Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Thanks,
Chanwoo Choi
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