请问为什么用互斥量的现象是按一下按键还会出现抖动识别问题

我的需求是，按一下按键灯只闪烁一次，解决轮询读取按键中抖动的问题，理论上线程2获得互斥量期间线程1不是不会识别的吗？为什么还会出现抖动识别问题，按一下灯还是会闪2-3次呢？
如下是我代码：

/* USER CODE BEGIN 0 /
static void thread1_entry(void parameter)
{
while(1)
{
rt_err_t result;
result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
if (result == RT_EOK)
{
while(1)
{
if(!HAL_GPIO_ReadPin(GPIOE, GPIO_PIN_4))
{
rt_mutex_release(mutex);
rt_thread_mdelay(200);
break;
}
// rt_thread_mdelay(100);
}
}
}
static void thread2_entry(void parameter)
{
while(1)
{
rt_err_t result;
result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
if (result == RT_EOK)
{
HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, GPIO_PIN_RESET);
rt_thread_mdelay(500);
HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, GPIO_PIN_SET);
rt_thread_mdelay(500);
// HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_5);
rt_mutex_release(mutex);
// rt_thread_mdelay(400);
}
}
}
/ USER CODE END 0 /
/
[url=home.php?mod=space&uid=2666770]@Brief[/url] The application entry point.
@retval int
/
int main(void)
{
/ USER CODE BEGIN 1 /
/ 创建互斥锁 /
rt_err_t result;
mutex = rt_mutex_create("mutex", RT_IPC_FLAG_PRIO);
if (mutex == RT_NULL)
{
rt_kprintf("create dynamic mutex failed.\n");
return -1;
}
result = rt_event_init(&event, "event", RT_IPC_FLAG_PRIO);
if (result != RT_EOK)
{
rt_kprintf("init event failed.\n");
return -1;
}
/ Initialize all configured peripherals /
MX_GPIO_Init();
/ USER CODE BEGIN 2 /
/ 创建线程 1，名称是 thread1，入口是 thread1_entry/
Key_scanf = rt_thread_create("thread1",
thread1_entry, RT_NULL,
THREAD_STACK_SIZE,
THREAD_PRIORITY, THREAD_TIMESLICE);
/* 如果获得线程控制块，启动这个线程 /
if (Key_scanf != RT_NULL)
rt_thread_startup(Key_scanf);
Key_handler = rt_thread_create("thread2",
thread2_entry, RT_NULL,
THREAD_STACK_SIZE,
THREAD_PRIORITY, THREAD_TIMESLICE);
/ 如果获得线程控制块，启动这个线程 /
if (Key_handler != RT_NULL)
rt_thread_startup(Key_handler);
/ USER CODE END 2 /
/ Infinite loop /
/ USER CODE BEGIN WHILE /
/ USER CODE END 3 /
}
/ USER CODE BEGIN 0 /
static void thread1_entry(void parameter)
{
while(1)
{
rt_err_t result;
result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
if (result == RT_EOK)
{
while(1)
{
if(!HAL_GPIO_ReadPin(GPIOE, GPIO_PIN_4))
{
rt_mutex_release(mutex);
rt_thread_mdelay(200);
break;
}
// rt_thread_mdelay(100);
}
}
}
static void thread2_entry(void parameter)
{
while(1)
{
rt_err_t result;
result = rt_mutex_take(mutex, RT_WAITING_FOREVER);
if (result == RT_EOK)
{
HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, GPIO_PIN_RESET);
rt_thread_mdelay(500);
HAL_GPIO_WritePin(GPIOE, GPIO_PIN_5, GPIO_PIN_SET);
rt_thread_mdelay(500);
// HAL_GPIO_TogglePin(GPIOE, GPIO_PIN_5);
rt_mutex_release(mutex);
// rt_thread_mdelay(400);
}
}
}
/ USER CODE END 0 /
/
@brief The application entry point.
@retval int
/
int main(void)
{
/ USER CODE BEGIN 1 /
/ 创建互斥锁 /
rt_err_t result;
mutex = rt_mutex_create("mutex", RT_IPC_FLAG_PRIO);
if (mutex == RT_NULL)
{
rt_kprintf("create dynamic mutex failed.\n");
return -1;
}
result = rt_event_init(&event, "event", RT_IPC_FLAG_PRIO);
if (result != RT_EOK)
{
rt_kprintf("init event failed.\n");
return -1;
}
/ Initialize all configured peripherals /
MX_GPIO_Init();
/ USER CODE BEGIN 2 /
/ 创建线程 1，名称是 thread1，入口是 thread1_entry/
Key_scanf = rt_thread_create("thread1",
thread1_entry, RT_NULL,
THREAD_STACK_SIZE,
THREAD_PRIORITY, THREAD_TIMESLICE);
/* 如果获得线程控制块，启动这个线程 /
if (Key_scanf != RT_NULL)
rt_thread_startup(Key_scanf);
Key_handler = rt_thread_create("thread2",
thread2_entry, RT_NULL,
THREAD_STACK_SIZE,
THREAD_PRIORITY, THREAD_TIMESLICE);
/ 如果获得线程控制块，启动这个线程 /
if (Key_handler != RT_NULL)
rt_thread_startup(Key_handler);
/ USER CODE END 2 /
/ Infinite loop /
/ USER CODE BEGIN WHILE /
/ USER CODE END 3 */
}