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Date:   Mon, 5 Apr 2021 17:26:46 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc:     Lars-Peter Clausen <lars@metafoo.de>, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] iio: hrtimer-trigger: Fix potential integer
 overflow in iio_hrtimer_store_sampling_frequency
Message-ID: <20210405172646.6a9f1b7d@jic23-huawei>
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On Mon, 29 Mar 2021 15:58:17 -0500
"Gustavo A. R. Silva" <gustavoars@kernel.org> wrote:

> Add suffix ULL to constant 1000 in order to avoid a potential integer
> overflow and give the compiler complete information about the proper
> arithmetic to use. Notice that this constant is being used in a context
> that expects an expression of type unsigned long long, but it's
> currently evaluated using 32-bit arithmetic.
> 
> Addresses-Coverity-ID: 1503062 ("Unintentional integer overflow")
> Fixes: dafcf4ed8392 ("iio: hrtimer: Allow sub Hz granularity")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks, Applied to the togreg branch of iio.git and pushed out as testing
for 0-day to poke at it.

Thanks,

Jonathan

> ---
>  drivers/iio/trigger/iio-trig-hrtimer.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/trigger/iio-trig-hrtimer.c b/drivers/iio/trigger/iio-trig-hrtimer.c
> index 51e362f091c2..716c795d08fb 100644
> --- a/drivers/iio/trigger/iio-trig-hrtimer.c
> +++ b/drivers/iio/trigger/iio-trig-hrtimer.c
> @@ -63,7 +63,7 @@ ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,
>  	if (integer < 0 || fract < 0)
>  		return -ERANGE;
>  
> -	val = fract + 1000 * integer;  /* mHz */
> +	val = fract + 1000ULL * integer;  /* mHz */
>  
>  	if (!val || val > UINT_MAX)
>  		return -EINVAL;