drm/amd/amdgpu: Avoid fault when allocating an empty buffer object

Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

@@ -348,7 +348,8 @@ int amdgpu_bo_create_kernel(struct amdgpu_device *adev,
 	if (r)
 		return r;
 
-	amdgpu_bo_unreserve(*bo_ptr);
+	if (*bo_ptr)
+		amdgpu_bo_unreserve(*bo_ptr);
 
 	return 0;
 }