[Intel-gfx] [PATCH] drm/i915: Assert that the vma->fence_size doesn't overflow and wraparound

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> A large object may need an invalid fence larger than u32 and so wrap. No
> hardware can support such large fences, so it is safe to leave the check
> as an assert.
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>

> ---
>  drivers/gpu/drm/i915/i915_vma.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index 68e66ffb95e8..3597e3c01342 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -115,6 +115,7 @@ vma_create(struct drm_i915_gem_object *obj,
>  						      i915_gem_object_get_tiling(obj),
>  						      i915_gem_object_get_stride(obj));
>  		GEM_BUG_ON(!IS_ALIGNED(vma->fence_size, I915_GTT_MIN_ALIGNMENT));
> +		GEM_BUG_ON(vma->fence_size < vma->size); /* overflow */
>  
>  		vma->fence_alignment = i915_gem_fence_alignment(vm->i915, vma->size,
>  								i915_gem_object_get_tiling(obj),
> -- 
> 2.11.0
>
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