解决：查看 FreeRTOSConfig.h 文件中配置的宏 #define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY ，即系统可管理最高中断优先级。查看你配置的串口中断优先级是否比该宏定义的优先级低，如果不是，则要修改。
- 例如
- 若此时我将串口1(或串口2)的抢占优先级更改为 2（1~4均可）都会产生如上警告。
// 文件 main.cNVIC_PriorityGroupConfig(NVIC_PriorityGroup_4); // 中断组 4// 文件 FreeRTOSConfig.h：#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY 5 //RTOS系统可管理的最高中断优先级// 文件 usart.c://Usart1 NVIC 配置NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority= 8;//抢占优先级8NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; //子优先级0NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); USART_ITConfig(USART2, USART_IT_RXNE, ENABLE); nvicInitStruct.NVIC_IRQChannel = USART2_IRQn;nvicInitStruct.NVIC_IRQChannelCmd = ENABLE;nvicInitStruct.NVIC_IRQChannelPreemptionPriority = 7; //抢占优先级7nvicInitStruct.NVIC_IRQChannelSubPriority = 0; //子优先级0NVIC_Init(&nvicInitStruct);