task_scheduler: Don't allow awaiting from Io Scheduler's task.

This is dangerous because the main task calls IoScheduler::await
frequently. If the main task waits for the Io Scheduler
and the scheduler waits for the main task, we deadlock.

Author: rtrbt

software/src/modules/io_scheduler/io_scheduler.h

@@ -112,6 +112,13 @@ class IoScheduler final : public IModule
         }
     }
 
+    [[gnu::always_inline]]
+    void assert_task_inactive(const char *error_message) const {
+        if (xTaskGetCurrentTaskHandle() == task_handle) {
+            esp_system_abort(error_message);
+        }
+    }
+
 private:
     [[noreturn]] void task_loop();
     [[noreturn]] static void task_fn(void *arg);

software/src/modules/task_scheduler/module.ini

@@ -4,6 +4,7 @@ Requires = Event Log
            Task Scheduler
 
 Optional = Debug
+           Io Scheduler
 
 ; The task scheduler has no dependencies before the loop
 ; and starts the handling of the pre_reboot phase

software/src/modules/task_scheduler/task_scheduler.cpp

@@ -374,6 +374,11 @@ bool TaskScheduler::await(uint64_t task_id, millis_t millis_to_wait)
     if (strcmp(pcTaskGetName(nullptr), TCPIP_THREAD_NAME) == 0) {
         esp_system_abort("Calling TaskScheduler::await is not allowed in the TCP/IP thread!");
     }
+#if MODULE_IO_SCHEDULER_AVAILABLE()
+    // This is dangerous because the main task calls IoScheduler::await frequently.
+    // If the main task waits for the Io Scheduler and the scheduler waits for the main task, we deadlock.
+    io_scheduler.assert_task_inactive("Calling TaskScheduler::await is not allowed in the Io Scheduler thread!");
+#endif
 #endif
     if (task_id == 0) {
         logger.printfln("Attempted to await task 0");