diff --git a/platforms/common/include/px4_platform_common/app.h b/platforms/common/include/px4_platform_common/app.h
index bb2b923d3f0..0f8e2b13beb 100644
--- a/platforms/common/include/px4_platform_common/app.h
+++ b/platforms/common/include/px4_platform_common/app.h
@@ -40,6 +40,8 @@
 
 #pragma once
 
+#include <px4_platform_common/atomic.h>
+
 namespace px4
 {
 
@@ -48,17 +50,17 @@ class AppState
 public:
 	~AppState() {}
 
-	AppState() : _exitRequested(false), _isRunning(false) {}
+	AppState() {}
 
-	bool exitRequested() { return _exitRequested; }
-	void requestExit() { _exitRequested = true; }
+	bool exitRequested() { return _exitRequested.load(); }
+	void requestExit() { _exitRequested.store(true); }
 
-	bool isRunning() { return _isRunning; }
-	void setRunning(bool running) { _isRunning = running; }
+	bool isRunning() { return _isRunning.load(); }
+	void setRunning(bool running) { _isRunning.store(running); }
 
 protected:
-	bool _exitRequested;
-	bool _isRunning;
+	px4::atomic_bool _exitRequested{false};
+	px4::atomic_bool _isRunning{false};
 private:
 	AppState(const AppState &);
 	const AppState &operator=(const AppState &);
diff --git a/platforms/nuttx/src/px4/common/tasks.cpp b/platforms/nuttx/src/px4/common/tasks.cpp
index 9ad860dc182..bffb270e264 100644
--- a/platforms/nuttx/src/px4/common/tasks.cpp
+++ b/platforms/nuttx/src/px4/common/tasks.cpp
@@ -40,6 +40,7 @@
 #include <px4_platform_common/px4_config.h>
 #include <px4_platform_common/log.h>
 #include <px4_platform_common/tasks.h>
+#include <px4_platform_common/time.h>
 
 #include <nuttx/board.h>
 #include <nuttx/kthread.h>
@@ -91,6 +92,16 @@ int px4_task_delete(int pid)
 	return task_delete(pid);
 }
 
+int px4_task_join(int pid)
+{
+	// Wait for the task to exit by polling whether it still exists
+	while (kill(pid, 0) == 0) {
+		px4_usleep(10000);
+	}
+
+	return 0;
+}
+
 const char *px4_get_taskname(void)
 {
 #if CONFIG_TASK_NAME_SIZE > 0 && (defined(__KERNEL__) || defined(CONFIG_BUILD_FLAT))