--- a/src/hotspot/share/gc/z/zMarkTerminate.inline.hpp	Mon Nov 25 12:31:39 2019 +0100
+++ b/src/hotspot/share/gc/z/zMarkTerminate.inline.hpp	Mon Nov 25 12:32:07 2019 +0100
@@ -33,7 +33,7 @@
     _nworking_stage1(0) {}
 
 inline bool ZMarkTerminate::enter_stage(volatile uint* nworking_stage) {
-  return Atomic::sub(1u, nworking_stage) == 0;
+  return Atomic::sub(nworking_stage, 1u) == 0;
 }
 
 inline void ZMarkTerminate::exit_stage(volatile uint* nworking_stage) {