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

[Chris Wilson]

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>
---
 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