--- thread.c.orig	Wed Aug  3 14:10:10 2011
+++ thread.c	Wed Aug  3 14:10:12 2011
@@ -429,6 +429,14 @@ thread_start_func_2(rb_thread_t *th, VALUE *stack_star
     rb_thread_t *join_th;
     rb_thread_t *main_th;
     VALUE errinfo = Qnil;
+
+    if (GET_VM()->inhibit_thread_creation) {
+	thread_debug("not starting thread due to interpreter shutdown: %p\n", (void *)th);
+	thread_cleanup_func(th, FALSE);
+	st_delete(th->vm->living_threads, th, NULL);
+	return 1;
+    }
+
 # ifdef USE_SIGALTSTACK
     void rb_register_sigaltstack(rb_thread_t *th);