diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp
index 70d73822..4492edc3 100644
--- a/src/libcamera/camera_manager.cpp
+++ b/src/libcamera/camera_manager.cpp
@@ -178,7 +178,10 @@ void CameraManager::Private::cleanup()
 	 * process deletion requests from the thread's message queue as the event
 	 * loop is not in action here.
 	 */
+	mutex_.lock();
 	cameras_.clear();
+	mutex_.unlock();
+
 	dispatchMessages(Message::Type::DeferredDelete);
 
 	enumerator_.reset(nullptr);