--- old/src/hotspot/share/gc/epsilon/epsilonHeap.cpp	2020-04-28 11:55:47.555734909 +0800
+++ new/src/hotspot/share/gc/epsilon/epsilonHeap.cpp	2020-04-28 11:55:47.391735750 +0800
@@ -296,6 +296,11 @@
   _space->object_iterate(cl);
 }
 
+// No workGang for EpsilonHeap, work serially with thread 0
+void EpsilonHeap::run_task(AbstractGangTask* task) {
+  task->work(0);
+}
+
 void EpsilonHeap::print_on(outputStream *st) const {
   st->print_cr("Epsilon Heap");