diff --git a/src/thread/thread.c b/src/thread/thread.c
index c332d42..1bb1680 100644
--- a/src/thread/thread.c
+++ b/src/thread/thread.c
@@ -282,6 +282,7 @@ void __attribute__((constructor)) setup_main_thread()
     main->id = main;
     main->status = 0;
     main->retvalue = NULL;
+    main->last_waited = NULL;
     running = main;
 
     // Create a context with static stack to clean everything at the end.