PM2.0外部中断唤醒后程序执行顺序异常为什么会发生这种情况呢

设备为stm32L071，rtt是github上下载的最新版4.1.1。在调试pm功能时遇到问题：
1.可以进入STOP模式，tickless使用lptim，工作正常，软件定时器可以主动唤醒。
2.当使用外部中断唤醒stop模式后，串口工作不正常，debug发现唤醒后竟然先执行了中断服务函数，然后切换到等待信号量的线程，直到idle后才会执行中的睡眠前的代码处，这时才执行恢复时钟函数。
pm睡眠前应该是禁用了全局中断的，只发生pending不执行ISR才对，为什么会有这种问题呢？

static void rx_thread_entry(void *param)
{
while(1)
{
if (rt_sem_take(rx_sem, RT_WAITING_FOREVER) == RT_EOK)
{
rt_pm_sleep_request(PM_BOARD_ID, PM_SLEEP_MODE_NONE);
do something //此时串口异常，LOG等功能输出乱码
rt_thread_mdelay(5);  //执行到此处，才跳转到睡眠前位置，恢复时钟
rt_thread_mdelay(5000);
rt_pm_sleep_release(PM_BOARD_ID, PM_SLEEP_MODE_NONE);
}
}
}
void lora_rx_irq_callback(void *parameter)
{
rt_sem_release(rx_sem); //先执行此行，释放信号量
}
pm适配代码如下：

static void sleep(struct rt_pm *pm, uint8_t mode)

{
switch (mode)
{
case PM_SLEEP_MODE_NONE:
break;
case PM_SLEEP_MODE_IDLE:
case PM_SLEEP_MODE_LIGHT:
/* Enter SLEEP Mode, Main regulator is ON /
HAL_PWR_EnterSLEEPMode(PWR_MAINREGULATOR_ON, PWR_SLEEPENTRY_WFI);
break;
case PM_SLEEP_MODE_DEEP:
/ Disable SysTick interrupt /
CLEAR_BIT(SysTick->CTRL, (rt_uint32_t)SysTick_CTRL_TICKINT_Msk);
/ Enable the Ultra Low Power mode and the fast wake up /
SET_BIT(PWR->CR, PWR_CR_ULP | PWR_CR_FWU);
/ Select HSI as system clock source after Wake Up from Stop mode /
//__HAL_RCC_WAKEUPSTOP_CLK_CONFIG(RCC_STOP_WAKEUPCLOCK_HSI);
/ Enter STOP mode /
HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
/ Disable the Ultra Low Power mode and the fast wake up /
CLEAR_BIT(PWR->CR, PWR_CR_ULP | PWR_CR_FWU);
/ Enable SysTick interrupt /
SET_BIT(SysTick->CTRL, (rt_uint32_t)SysTick_CTRL_TICKINT_Msk);
/ Re-configure the system clock /
SystemClock_ReConfig();
break;
case PM_SLEEP_MODE_STANDBY:
case PM_SLEEP_MODE_SHUTDOWN:
__HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
/ Enter STANDBY mode */
HAL_PWR_EnterSTANDBYMode();
break;
default:
RT_ASSERT(0);
break;
}
}