[PATCH] Fix SIGSEGV in libdrm for heigth = 0 and width = 0

[Damien Lespiau]

On Fri, Nov 07, 2014 at 07:43:04PM +0100, Thomas Meyer wrote:
> 
> drm_intel_gem_bo_free() crashes because the list bo_gem->vma_list is not
> yet initialised, but the error path tries to free it.
> 
> See also https://bugs.freedesktop.org/show_bug.cgi?id=75844
> 
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Thomas Meyer <thomas at m3y3r.de>

Thanks for the patch and review tag. Sorry it took so long to push, it
wasn't clear who was going to do it.

-- 
Damien

> ---
> 
> diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
> index f2f4fea..b3e9dba 100644
> --- a/intel/intel_bufmgr_gem.c
> +++ b/intel/intel_bufmgr_gem.c
> @@ -759,15 +759,16 @@ retry:
>  		bo_gem->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
>  		bo_gem->stride = 0;
>  
> +		/* drm_intel_gem_bo_free calls DRMLISTDEL() for an uninitialized
> +		   list (vma_list), so better set the list head here */
> +		DRMINITLISTHEAD(&bo_gem->name_list);
> +		DRMINITLISTHEAD(&bo_gem->vma_list);
>  		if (drm_intel_gem_bo_set_tiling_internal(&bo_gem->bo,
>  							 tiling_mode,
>  							 stride)) {
>  		    drm_intel_gem_bo_free(&bo_gem->bo);
>  		    return NULL;
>  		}
> -
> -		DRMINITLISTHEAD(&bo_gem->name_list);
> -		DRMINITLISTHEAD(&bo_gem->vma_list);
>  	}
>  
>  	bo_gem->name = name;
> 
> 
>