[PATCH] drm/modes: Prevent division by zero htotal

Daniel Vetter daniel at ffwll.ch
Wed Jan 23 10:56:23 UTC 2019


On Wed, Jan 23, 2019 at 03:28:59PM +0800, Tina Zhang wrote:
> This patch prevents division by zero htotal.

How did you manage to get here with htotal == 0? This needs backtraces
(or if this is just about static checkers, a mention of that).
-Daniel

> 
> Signed-off-by: Tina Zhang <tina.zhang at intel.com>
> Cc: Adam Jackson <ajax at redhat.com>
> Cc: Dave Airlie <airlied at redhat.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> ---
>  drivers/gpu/drm/drm_modes.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> index adce9a2..59b92b1 100644
> --- a/drivers/gpu/drm/drm_modes.c
> +++ b/drivers/gpu/drm/drm_modes.c
> @@ -751,7 +751,7 @@ int drm_mode_hsync(const struct drm_display_mode *mode)
>  	if (mode->hsync)
>  		return mode->hsync;
>  
> -	if (mode->htotal < 0)
> +	if (mode->htotal <= 0)
>  		return 0;
>  
>  	calc_val = (mode->clock * 1000) / mode->htotal; /* hsync in Hz */
> -- 
> 2.7.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch


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