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SubjectRe: [PATCH][next] drm/amd/display: Fix potential integer overflow
On Wed, Feb 10, 2021 at 4:23 PM Gustavo A. R. Silva
<gustavoars@kernel.org> wrote:
>
> Fix potential integer overflow by casting actual_calculated_clock_100hz
> to u64, in order to give the compiler complete information about the
> proper arithmetic to use.
>
> Notice that such variable is used in a context that expects
> an expression of type u64 (64 bits, unsigned) and the following
> expression is currently being evaluated using 32-bit arithmetic:
>
> actual_calculated_clock_100hz * post_divider
>
> Fixes: 7a03fdf628af ("drm/amd/display: fix 64bit division issue on 32bit OS")
> Addresses-Coverity-ID: 1501691 ("Unintentional integer overflow")
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Applied. Thanks!

Alex


> ---
> drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> index bc942725b9d8..dec58b3c42e4 100644
> --- a/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_clock_source.c
> @@ -240,7 +240,7 @@ static bool calc_fb_divider_checking_tolerance(
> pll_settings->calculated_pix_clk_100hz =
> actual_calculated_clock_100hz;
> pll_settings->vco_freq =
> - div_u64(actual_calculated_clock_100hz * post_divider, 10);
> + div_u64((u64)actual_calculated_clock_100hz * post_divider, 10);
> return true;
> }
> return false;
> --
> 2.27.0
>
> _______________________________________________
> amd-gfx mailing list
> amd-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx

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