rt_scheduler_stack_check栈溢出检测的边界

发布于 2024-04-09 11:09:12 浏览：460 订阅该版

![屏幕截图 2024-04-09 101225.png](https://oss-club.rt-thread.org/uploads/20240409/0ef41635873de7bf6d9b13746567b236.png.webp)

近日，在阅读线程调度关于栈空间溢出检测的代码，有几处不明的地方，希望有码友解答一番。

上边的黄色部分是栈指针取值边界的问题，我感觉应该是开区间，SP取值栈空间顶部没有问题。
蓝色部分是判断重复的问题，是否因该如下方黄色部分一样，为R4~R11压栈操作预留空间。

诚邀码友积极回复。

```c
#ifdef RT_USING_OVERFLOW_CHECK
void rt_scheduler_stack_check(struct rt_thread *thread)
{
    RT_ASSERT(thread != RT_NULL);

#ifdef RT_USING_SMART
#ifndef ARCH_MM_MMU
    struct rt_lwp *lwp = thread ? (struct rt_lwp *)thread->lwp : 0;

/* if stack pointer locate in user data section skip stack check. */
    if (lwp && ((rt_uint32_t)thread->sp > (rt_uint32_t)lwp->data_entry &&
    (rt_uint32_t)thread->sp <= (rt_uint32_t)lwp->data_entry + (rt_uint32_t)lwp->data_size))
    {
        return;
    }
#endif /* not defined ARCH_MM_MMU */
#endif /* RT_USING_SMART */

#ifndef RT_USING_HW_STACK_GUARD
#ifdef ARCH_CPU_STACK_GROWS_UPWARD
    if (*((rt_uint8_t *)((rt_ubase_t)thread->stack_addr + thread->stack_size - 1)) != '#' ||
#else
    if (*((rt_uint8_t *)thread->stack_addr) != '#' ||
#endif /* ARCH_CPU_STACK_GROWS_UPWARD */
        (rt_ubase_t)thread->sp <= (rt_ubase_t)thread->stack_addr ||
        (rt_ubase_t)thread->sp >
        (rt_ubase_t)thread->stack_addr + (rt_ubase_t)thread->stack_size)
    {
        rt_base_t dummy = 1;

LOG_E("thread:%s stack overflow\n", thread->parent.name);

while (dummy);
    }
#endif /* RT_USING_HW_STACK_GUARD */
#ifdef ARCH_CPU_STACK_GROWS_UPWARD
#ifndef RT_USING_HW_STACK_GUARD
    else if ((rt_ubase_t)thread->sp > ((rt_ubase_t)thread->stack_addr + thread->stack_size))
#else
    if ((rt_ubase_t)thread->sp > ((rt_ubase_t)thread->stack_addr + thread->stack_size))
#endif
    {
        LOG_W("warning: %s stack is close to the top of stack address.\n",
                   thread->parent.name);
    }
#else
#ifndef RT_USING_HW_STACK_GUARD
    else if ((rt_ubase_t)thread->sp <= ((rt_ubase_t)thread->stack_addr + 32))
#else
    if ((rt_ubase_t)thread->sp <= ((rt_ubase_t)thread->stack_addr + 32))
#endif
    {
        LOG_W("warning: %s stack is close to end of stack address.\n",
                   thread->parent.name);
    }
#endif /* ARCH_CPU_STACK_GROWS_UPWARD */
```