Re: [PATCH v2 08/13] media: ar0521: don't overflow when checking PLL values

["Krzysztof Hałasa" <khalasa@piap.pl>]

Hi Mauro,

Mauro Carvalho Chehab <mchehab+huawei@kernel.org> writes:

> The PLL checks are comparing 64 bit integers with 32 bit
> ones, as reported by Coverity. Depending on the values of
> the variables, this may underflow.
>
> Fix it ensuring that both sides of the expression are u64.
>
> Fixes: 852b50aeed15 ("media: On Semi AR0521 sensor driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Acked-by: Krzysztof Hałasa <khalasa@piap.pl>

> --- a/drivers/media/i2c/ar0521.c
> +++ b/drivers/media/i2c/ar0521.c
> @@ -255,10 +255,10 @@ static u32 calc_pll(struct ar0521_dev *sensor, u32 freq, u16 *pre_ptr, u16 *mult
>                         continue; /* Minimum value */
>                 if (new_mult > 254)
>                         break; /* Maximum, larger pre won't work either */
> -               if (sensor->extclk_freq * (u64)new_mult < AR0521_PLL_MIN *
> +               if (sensor->extclk_freq * (u64)new_mult < (u64)AR0521_PLL_MIN *
>                     new_pre)
>                         continue;
> -               if (sensor->extclk_freq * (u64)new_mult > AR0521_PLL_MAX *
> +               if (sensor->extclk_freq * (u64)new_mult > (u64)AR0521_PLL_MAX *
>                     new_pre)
>                         break; /* Larger pre won't work either */
>                 new_pll = div64_round_up(sensor->extclk_freq * (u64)new_mult,
-- 
Krzysztof "Chris" Hałasa

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