--- a/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Mon Mar 26 16:51:43 2018 +0200
+++ b/src/hotspot/share/gc/g1/g1CollectedHeap.cpp	Mon Mar 26 16:51:43 2018 +0200
@@ -4214,7 +4214,8 @@
   if (collector_state()->during_initial_mark_pause()) {
     oop pll_head = Universe::reference_pending_list();
     if (pll_head != NULL) {
-      _cm->mark_in_next_bitmap(pll_head);
+      // Any valid worker id is fine here as we are in the VM thread and single-threaded.
+      _cm->mark_in_next_bitmap(0 /* worker_id */, pll_head);
     }
   }