--- a/src/hotspot/share/gc/shared/collectedHeap.cpp	Fri Mar 16 19:13:13 2018 +0100
+++ b/src/hotspot/share/gc/shared/collectedHeap.cpp	Tue Mar 20 15:59:36 2018 +0100
@@ -585,3 +585,12 @@
 void CollectedHeap::post_initialize() {
   initialize_serviceability();
 }
+
+oop CollectedHeap::pin_object(JavaThread* thread, oop o) {
+  GCLocker::lock_critical(thread);
+  return o;
+}
+
+void CollectedHeap::unpin_object(JavaThread* thread, oop o) {
+  GCLocker::unlock_critical(thread);
+}