Get size before freeing interfaces

src/datawizard/interfaces/data_interface.c

@@ -553,10 +553,11 @@ static void _starpu_data_unregister(starpu_data_handle_t handle, unsigned cohere
 	/* Wait for finished requests to release the handle */
 	_starpu_spin_lock(&handle->header_lock);
 
+	size_t size = _starpu_data_get_size(handle);
+
 	_starpu_data_free_interfaces(handle);
 
 	/* Destroy the data now */
-	size_t size = _starpu_data_get_size(handle);
 	unsigned node;
 	for (node = 0; node < STARPU_MAXNODES; node++)
 	{