select不返回麻烦大神指点一下可能出问题的地方

项目中使用pipe通道，两个fd，一个线程读pipe的数据，一个线程写pipe的数据，优先级读的高一些，写的线程100ms写一次，读的线程判了select，设置了超时3s退出（系统配置的是硬件时钟，软时钟没启动），系统运行一段时间后发现读线程的select不返回了，类似于在select里进入了死循环，看了内核的select.c poll.c pipe.c timer.c的代码，去官网搜了已知bug，这几个文件我更新到了最新，但是现象依然存在。现象出现时，我查看了这两线程都处于ready状态，但是运行计数都不在增加，现在就是没有排查思路了，麻烦大神指点一下可能出问题的地方，万分感谢。

自己有几个疑问：1.如果是超时出了问题，那么线程应该处于挂起才对，在poll_wait_out函数中设置定时器时先挂起线程。

static int poll_wait_timeout(struct rt_poll_table *pt, int msec)
{
rt_int32_t timeout;
int ret = 0;
struct rt_thread *thread;
rt_base_t level;
thread = pt->polling_thread;
timeout = rt_tick_from_millisecond(msec);
level = rt_hw_interrupt_disable();
if (timeout != 0 && !pt->triggered)
{
rt_thread_suspend(thread);
if (timeout > 0)
{
rt_timer_control(&(thread->thread_timer),
RT_TIMER_CTRL_SET_TIME,
&timeout);
rt_timer_start(&(thread->thread_timer));
}
rt_hw_interrupt_enable(level);
rt_schedule();
level = rt_hw_interrupt_disable();
}
ret = !pt->triggered;
rt_hw_interrupt_enable(level);
return ret;
}

2.在_poll_add函数中

static void _poll_add(rt_wqueue_t *wq, rt_pollreq_t *req)
{
struct rt_poll_table *pt;
struct rt_poll_node *node;
node = (struct rt_poll_node *)rt_malloc(sizeof(struct rt_poll_node));
if (node == RT_NULL)
return;
pt = rt_container_of(req, struct rt_poll_table, req);
node->wqn.key = req->_key;
rt_list_init(&(node->wqn.list));
node->wqn.polling_thread = pt->polling_thread;
node->wqn.wakeup = __wqueue_pollwake;
node->next = pt->nodes;
node->pt = pt;
pt->nodes = node;
rt_wqueue_add(wq, &node->wqn);
}

使用rt_malloc分配了堆内存，但是我去查看并未发现有释放堆的操作

void rt_wqueue_wakeup(rt_wqueue_t *queue, void *key)
{
rt_base_t level;
register int need_schedule = 0;
rt_list_t *queue_list;
struct rt_list_node *node;
struct rt_wqueue_node entry;
queue_list = &(queue->waiting_list);
level = rt_hw_interrupt_disable();
/ set wakeup flag in the queue */
queue->flag = RT_WQ_FLAG_WAKEUP;
if (!(rt_list_isempty(queue_list)))
{
for (node = queue_list->next; node != queue_list; node = node->next)
{
entry = rt_list_entry(node, struct rt_wqueue_node, list);
if (entry->wakeup(entry, key) == 0)
{
rt_thread_resume(entry->polling_thread);
need_schedule = 1;
rt_wqueue_remove(entry);
break;
}
}
}
rt_hw_interrupt_enable(level);
if (need_schedule)
rt_schedule();
}
void rt_wqueue_remove(struct rt_wqueue_node *node)
{
rt_base_t level;
level = rt_hw_interrupt_disable();
rt_list_remove(&(node->list));
rt_hw_interrupt_enable(level);
}
rt_inline void rt_list_remove(rt_list_t *n)
{
n->next->prev = n->prev;
n->prev->next = n->next;
n->next = n->prev = n;
}