--- old/src/share/vm/gc_implementation/shenandoah/shenandoahConcurrentMark.hpp	2019-11-11 16:09:52.677343122 +0100
+++ new/src/share/vm/gc_implementation/shenandoah/shenandoahConcurrentMark.hpp	2019-11-11 16:09:52.591343126 +0100
@@ -32,6 +32,7 @@
 class ShenandoahStrDedupQueue;
 
 class ShenandoahConcurrentMark: public CHeapObj<mtGC> {
+  friend class ShenandoahTraversalGC;
 private:
   ShenandoahHeap* _heap;
   ShenandoahObjToScanQueueSet* _task_queues;