sem_destroy 调用后内存未被释放

发布于 2021-03-19 11:07:09 浏览：967 订阅该版

使用sem_init创建信号量，使用sem_destroy删除信号量。通过free查看内存使用情况，发现创建前后有84字节的SDRAM空间未被释放。

经过调试分析发现sem_destroy调用时，在rt_sem_trytake处会返回错误，导致无法释放内存。
如果在sem_destroy前先调用一次sem_post，程序会正常通过rt_sem_trytake，但会出现段错误：
```
(heade(header_ptr->magic & RT_MEMHEAP_USED) assertion fair at fuction:rt_memheap_free, line number:516
```

sem_init代码如下：
```c
    char name[RT_NAME_MAX];
    static rt_uint16_t psem_number = 0;

if (sem == RT_NULL)
    {
        rt_set_errno(EINVAL);

return -1;
    }

rt_snprintf(name, sizeof(name), "psem%02d", psem_number++);
    sem->sem = rt_sem_create(name, value, RT_IPC_FLAG_FIFO);
    if (sem == RT_NULL)
    {
        rt_set_errno(ENOMEM);

return -1;
    }

/* initialize posix semaphore */
    sem->refcount = 1;
    sem->unlinked = 0;
    sem->unamed = 1;
    /* lock posix semaphore 
```
sem_destroy的代码如下：
```
    rt_err_t result;

if ((!sem) || !(sem->unamed))
    {
        rt_set_errno(EINVAL);

return -1;
    }

/* lock posix semaphore list */
    rt_sem_take(&posix_sem_lock, RT_WAITING_FOREVER);
    result = rt_sem_trytake(sem->sem);
    if (result != RT_EOK)
    {
        rt_sem_release(&posix_sem_lock);
        rt_set_errno(EBUSY);

return -1;
    }

/* destroy an unamed posix semaphore */
    posix_sem_delete(sem);
    rt_sem_release(&posix_sem_lock);

return 0;
```