Re: [PATCH] drm/i915: add sanity check for partial view creation

From: Chris Wilson <chris@chris-wilson.co.uk>
To: Matthew Auld <matthew.auld@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: add sanity check for partial view creation
Date: Wed, 2 Mar 2016 14:42:05 +0000	[thread overview]
Message-ID: <20160302144205.GH30782@nuc-i3427.alporthouse.com> (raw)
In-Reply-To: <1456929209-18822-1-git-send-email-matthew.auld@intel.com>

On Wed, Mar 02, 2016 at 02:33:29PM +0000, Matthew Auld wrote:
> When binding pages for a partial view we should check that the offset +
> size is valid relative to the size of the gem object.
> 
> v2: Don't use pages->nents to determine the page count (Tvrtko Ursulin)
> 
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_gtt.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 7b8de85..2c49d043 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -3493,6 +3493,10 @@ intel_partial_pages(const struct i915_ggtt_view *view,
>  	struct sg_page_iter obj_sg_iter;
>  	int ret = -ENOMEM;
>  
> +	if (view->params.partial.offset + view->params.partial.size >

Handle overflow?

Why do it here and not at creation?

What bug are you fixing?

> +	    obj->base.size >> PAGE_SHIFT)
> +		return ERR_PTR(-EINVAL);

Is this a user error? Or just an internal programming bug.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre
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