请问FREERTOS下USART3中断工作2小时左右死机的原因？

求助，FREERTOS下USART3中断工作2小时左右死机，目前是测试程序，就中断接收1个数据，马上发送，请大家帮我看一下串口配置部分是否有问题？
void UART3_Configuration(void)
{
    //GPIO端口设置
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
     
    //使能串口3，PB，AFIO总线
//    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB|RCC_APB2Periph_AFIO, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE); //串口时钟配置
USART_DeInit(USART3);  //复位串口3

  //  RS485_CTL3_L();  //RECEIVE

    /* B10 USART3_Tx */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;       //推挽输出-TX
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    /* B11 USART3_Rx  */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入-RX
    GPIO_Init(GPIOB, &GPIO_InitStructure);
   
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART3,ENABLE);//复位串口 3
RCC_APB1PeriphResetCmd(RCC_APB1Periph_USART3,DISABLE);//停止复位

    USART_InitStructure.USART_BaudRate = 38400;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART3, &USART_InitStructure); //初始化串口

//Usart3 NVIC 配置
    NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1 ;//抢占优先级1
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;//子优先级0
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;//IRQ通道使能
NVIC_Init(&NVIC_InitStructure);//根据指定的参数初始化VIC寄存器
//串口3使用接收中断
    USART_ITConfig(USART3,USART_IT_RXNE,ENABLE);
//USART_ITConfig(USART3, USART_IT_TC, ENABLE);
USART_ClearITPendingBit(USART3, USART_IT_TC);
    /* Enable the USARTx */
    USART_Cmd(USART3, ENABLE);
     
   
}
void USART3_IRQHandler(void)
{
u8 uart3_data;
taskENTER_CRITICAL();
if(USART_GetITStatus(USART3, USART_IT_RXNE) != RESET)  
{
uart3_data =USART_ReceiveData(USART3);//读取接收到的数据   
}
taskEXIT_CRITICAL();
}
void USART3_SendChar(u8 ch)
{
    u16 i = 0;
    USART_SendData(USART3, ch);
    while(USART_GetFlagStatus(USART3, USART_FLAG_TC) == RESET && i < 3000)
   
}