5 ULOG初始化从系统堆申请内存块失败，进入断言RT_ASSERT(m != RT_NULL)

ulog.async_rbb = rt_rbb_create(RT_ALIGN(ULOG_ASYNC_OUTPUT_BUF_SIZE, RT_ALIGN_SIZE), ULOG_ASYNC_OUTPUT_STORE_LINES);

ULOG_ASYNC_OUTPUT_BUF_SIZE 1024
RT_ALIGN_SIZE 4
ULOG_ASYNC_OUTPUT_STORE_LINES  (ULOG_ASYNC_OUTPUT_BUF_SIZE * 3 / 2 / 80)
rbb = (rt_rbb_t)rt_malloc(sizeof(struct rt_rbb));--》 ptr = _MEM_MALLOC(size);