From: "james qian wang (Arm Technology China)" <james.qian.wang@arm.com>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Liviu Dudau <Liviu.Dudau@arm.com>,
Brian Starkey <Brian.Starkey@arm.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>, nd <nd@arm.com>
Subject: Re: drm/komeda: Fix potential integer overflow in komeda_crtc_update_clock_ratio
Date: Mon, 12 Aug 2019 10:18:11 +0000 [thread overview]
Message-ID: <20190812101805.GA3984@jamwan02-TSP300> (raw)
In-Reply-To: <20190812000801.GA29204@embeddedor>
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>
prev parent reply other threads:[~2019-08-12 10:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 0:08 [PATCH] drm/komeda: Fix potential integer overflow in komeda_crtc_update_clock_ratio Gustavo A. R. Silva
2019-08-12 10:18 ` james qian wang (Arm Technology China) [this message]
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