--- a/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Fri Oct 18 14:56:01 2019 +0200
+++ b/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp	Fri Oct 18 11:36:35 2019 -0400
@@ -2042,11 +2042,19 @@
   // Cleanup weak roots
   ShenandoahGCPhase phase(timing_phase);
   if (has_forwarded_objects()) {
-    ShenandoahForwardedIsAliveClosure is_alive;
-    ShenandoahUpdateRefsClosure keep_alive;
-    ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure>
-      cleaning_task(&is_alive, &keep_alive, num_workers);
-    _workers->run_task(&cleaning_task);
+    if (is_traversal_mode()) {
+      ShenandoahForwardedIsAliveClosure is_alive;
+      ShenandoahTraversalUpdateRefsClosure keep_alive;
+      ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahTraversalUpdateRefsClosure>
+        cleaning_task(&is_alive, &keep_alive, num_workers);
+      _workers->run_task(&cleaning_task);
+    } else {
+      ShenandoahForwardedIsAliveClosure is_alive;
+      ShenandoahUpdateRefsClosure keep_alive;
+      ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure>
+        cleaning_task(&is_alive, &keep_alive, num_workers);
+      _workers->run_task(&cleaning_task);
+    }
   } else {
     ShenandoahIsAliveClosure is_alive;
 #ifdef ASSERT