优化代码，修改 FALLTHROUGH 宏定义，增加递归互斥锁支持，改进调度器挂起和恢复逻辑，增强命令查找功能

sal/esp32/kernel/os_mutex.c

@@ -6,7 +6,7 @@ os_state os_mutex_create(os_mutex_t *mutex)
 {
     OS_ASS_HDL(!os_mutex_is_valid(mutex), mutex->handle);
 
-    mutex->handle = xSemaphoreCreateMutex();
+    mutex->handle = xSemaphoreCreateRecursiveMutex();
     if (mutex->handle == NULL)
     {
         OS_ERR("err %p\r\n", mutex->handle);
@@ -31,7 +31,7 @@ os_state os_mutex_lock(os_mutex_t *mutex, os_time_t wait_ms)
 
     OS_ASS_HDL(os_mutex_is_valid(mutex), mutex->handle);
 
-    ret = xSemaphoreTake(mutex->handle, os_calc_msec_to_ticks(wait_ms));
+    ret = xSemaphoreTakeRecursive(mutex->handle, os_calc_msec_to_ticks(wait_ms));
     if (ret != pdPASS)
     {
         OS_DBG("%s() fail @ %d, %u ms\n", __func__, __LINE__, wait_ms);
@@ -47,7 +47,7 @@ os_state os_mutex_unlock(os_mutex_t *mutex)
 
     OS_ASS_HDL(os_mutex_is_valid(mutex), mutex->handle);
 
-    ret = xSemaphoreGive(mutex->handle);
+    ret = xSemaphoreGiveRecursive(mutex->handle);
     if (ret != pdPASS)
     {
         OS_DBG("%s() fail @ %d\n", __func__, __LINE__);

sal/esp32/kernel/os_service.c

@@ -27,14 +27,7 @@ void os_int_exit(void)
 
 bool os_is_isr_context(void)
 {
-    if (int_flag)
-    {
-        return true;
-    }
-    else
-    {
-        return false;
-    }
+    return xPortInIsrContext() || (int_flag > 0);
 }
 
 void os_interrupt_disable(void)
@@ -49,12 +42,22 @@ void os_interrupt_enable(void)
 
 void os_scheduler_suspend(void)
 {
+    // 在进入临界区前检查是否在中断上下文中
+    if (os_is_isr_context())
+    {
+        OS_ERR("Called in isr"); // 在中断中不要挂起调度器，可能会导致死锁
+        return;
+    }
     vTaskSuspendAll();
 }
 
 void os_scheduler_resume(void)
 {
-    xTaskResumeAll();
+    // 只有在非中断上下文中才恢复调度器
+    if (!os_is_isr_context())
+    {
+        xTaskResumeAll();
+    }
 }
 
 bool os_scheduler_is_running(void)