diff --git a/runtime-light/stdlib/system/system-functions.h b/runtime-light/stdlib/system/system-functions.h
index 2bc407c5fc..297cf0d02d 100644
--- a/runtime-light/stdlib/system/system-functions.h
+++ b/runtime-light/stdlib/system/system-functions.h
@@ -105,6 +105,7 @@ inline kphp::coro::task<> f$die(mixed v = 0) noexcept {
 template<typename F>
 bool f$register_kphp_on_oom_callback(F&& /*callback*/) {
   kphp::log::warning("called stub register_kphp_on_oom_callback");
+  return true;
 }
 
 template<typename F>