* [PATCH] drm/komeda: Fix potential integer overflow in komeda_crtc_update_clock_ratio
@ 2019-08-12 0:08 Gustavo A. R. Silva
2019-08-12 10:18 ` james qian wang (Arm Technology China)
0 siblings, 1 reply; 3+ messages in thread
From: Gustavo A. R. Silva @ 2019-08-12 0:08 UTC (permalink / raw)
To: James (Qian) Wang, Liviu Dudau, Brian Starkey, David Airlie,
Daniel Vetter
Cc: dri-devel, linux-kernel, Gustavo A. R. Silva
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);
--
2.22.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: drm/komeda: Fix potential integer overflow in komeda_crtc_update_clock_ratio
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)
0 siblings, 0 replies; 3+ messages in thread
From: james qian wang (Arm Technology China) @ 2019-08-12 10:18 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: David Airlie, Liviu Dudau, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org, nd
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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dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: drm/komeda: Fix potential integer overflow in komeda_crtc_update_clock_ratio
@ 2019-08-12 10:18 ` james qian wang (Arm Technology China)
0 siblings, 0 replies; 3+ messages in thread
From: james qian wang (Arm Technology China) @ 2019-08-12 10:18 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Liviu Dudau, Brian Starkey, David Airlie, Daniel Vetter,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, nd
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>
^ permalink raw reply [flat|nested] 3+ messages in thread
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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)
2019-08-12 10:18 ` james qian wang (Arm Technology China)
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