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    SubjectRe: drm/komeda: Fix potential integer overflow in komeda_crtc_update_clock_ratio
    Date
    On Sun, Aug 11, 2019 at 07:08:01PM -0500, Gustavo A. R. Silva 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 u64, but it's currently evaluated
    > using 32-bit arithmetic.
    >
    > Addresses-Coverity-ID: 1485796 ("Unintentional integer overflow")
    > Fixes: ed22c6d9304d ("drm/komeda: Use drm_display_mode "crtc_" prefixed hardware timings")
    > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
    > ---
    > drivers/gpu/drm/arm/display/komeda/komeda_crtc.c | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
    > index fa9a4593bb37..624d257da20f 100644
    > --- a/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
    > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_crtc.c
    > @@ -27,7 +27,7 @@ static void komeda_crtc_update_clock_ratio(struct komeda_crtc_state *kcrtc_st)
    > return;
    > }
    >
    > - pxlclk = kcrtc_st->base.adjusted_mode.crtc_clock * 1000;
    > + pxlclk = kcrtc_st->base.adjusted_mode.crtc_clock * 1000ULL;
    > aclk = komeda_crtc_get_aclk(kcrtc_st);
    >
    > kcrtc_st->clock_ratio = div64_u64(aclk << 32, pxlclk);

    Thank you for the patch.

    Reviewed-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>

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