memset (v + old_alloc_bytes, 0, new_alloc_bytes - old_alloc_bytes);
CLIB_MEM_POISON (new + data_bytes, new_alloc_bytes - data_bytes);
memset (v + old_alloc_bytes, 0, new_alloc_bytes - old_alloc_bytes);
CLIB_MEM_POISON (new + data_bytes, new_alloc_bytes - data_bytes);