ESP32运行FreeRTOS基础程序触发Guru Meditation Error求助

问题背景 #

在ESP32上运行FreeRTOS基础程序，功能是将全局变量内容打印到串口监视器，但运行后出现非法指令panic。代码及错误信息如下：

原始代码 #

#if CONFIG_FREERTOS_UNICORE //this will return false (reading from config in freertos.h file), so we’ll set it to run on the second core app_cpu=1
static const BaseType_t app_cpu = 0;
#else
static const BaseType_t app_cpu = 1;
#endif


//global variable
char buffer[] = "Mary had a little lamb";

//task1
void Task1_Function( void *params)
{
  uint8_t i = 0;
  uint8_t msg_len = strlen(buffer);
  
  //read (print) whatever is in the buffer
  Serial.print("Task1: ");
  for(int i; i < msg_len; i++)
  {
    Serial.print(buffer[i]);
  }
  Serial.println();
  vTaskDelay(1000 / portTICK_PERIOD_MS);

}


//task2
//void Task1_Function( void *params)
//{


//}


void setup() 
{
  
  //Initialize Serial monitor
  Serial.begin(9600);

  BaseType_t status;
  TaskHandle_t task1_handler, task2_handler;

  
  //Task 1 Creation 
  status = xTaskCreatePinnedToCore(Task1_Function,
                       "Task-1-Function",
                       1024,  //This is stack size in words, in bytes for a 32bit miccrocontroller each word is 4 bytes. so 500*4 = 20000 bytes
                       NULL,  //no parameters passed
                       1,     //priority
                       &task1_handler,
                       app_cpu
                       );

  //check if task creation, memory allocation was sucessfull
  if (status != pdTRUE)
  {
    Serial.println("Error Task1 creation failed");     //using Arduino IDE
  }
  //Or you can use the assert
  //configASSERT(status == pdTRUE);

}


void loop() 
{
  // put your main code here, to run repeatedly:
  
}

运行错误信息 #

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0030,len:1156
load:0x40078000,len:11456
ho 0 tail 12 room 4
load:0x40080400,len:2972
entry 0x400805dc
Task1: Mary had a little lamb
Guru Meditation Error: Core  1 panic'ed (IllegalInstruction). Exception was unhandled.
Memory dump at 0x400d1428: 4ce5e8a3 00f01db8 b2808430
Core  1 register dump:
PC      : 0x400d142d  PS      : 0x00060b30  A0      : 0x00000000  A1      : 0x3ffb8d10  
A2      : 0x3ffc1058  A3      : 0x00000016  A4      : 0x3ffbdb60  A5      : 0x00000016  
A6      : 0x00000000  A7      : 0x00000000  A8      : 0x800d142d  A9      : 

问题分析 #

1. 核心原因：FreeRTOS任务函数未实现无限循环
   FreeRTOS的任务函数必须持续运行，不能执行完毕后返回。Task1_Function在执行一次打印和延迟后就退出了，这种行为会触发系统非法指令异常。

2. 次要问题：循环变量未初始化
   在Task1_Function的for循环中，重复声明了int i但未初始化，属于未定义行为，本次运行巧合打印出内容，但存在潜在风险。

修复后的代码 #

#if CONFIG_FREERTOS_UNICORE
static const BaseType_t app_cpu = 0;
#else
static const BaseType_t app_cpu = 1;
#endif

//global variable
char buffer[] = "Mary had a little lamb";

//task1
void Task1_Function( void *params)
{
  uint8_t msg_len = strlen(buffer);
  
  // FreeRTOS任务必须保持运行，添加无限循环
  while(true) {
    Serial.print("Task1: ");
    // 初始化循环变量，避免未定义行为
    for(uint8_t i = 0; i < msg_len; i++)
    {
      Serial.print(buffer[i]);
    }
    Serial.println();
    vTaskDelay(1000 / portTICK_PERIOD_MS);
  }
}

void setup() 
{
  Serial.begin(9600);

  BaseType_t status;
  TaskHandle_t task1_handler;

  //Task 1 Creation 
  status = xTaskCreatePinnedToCore(Task1_Function,
                       "Task-1-Function",
                       1024,
                       NULL,
                       1,
                       &task1_handler,
                       app_cpu
                       );

  if (status != pdTRUE)
  {
    Serial.println("Error Task1 creation failed");
  }
}

void loop() 
{
  // 空loop不影响，FreeRTOS任务已独立运行
}

修改说明 #

1. 添加while(true)无限循环：将打印和延迟逻辑放入循环内，确保任务函数持续运行，不会返回，彻底解决非法指令panic问题。
2. 修复循环变量：移除重复声明的int i，改为在循环内初始化uint8_t i = 0，消除未定义行为，同时与msg_len类型保持一致。
3. 清理冗余代码：移除未使用的task2_handler和重复的变量声明，简化代码结构。

内容的提问来源于stack exchange，提问作者tadm123