diff -r 56bf71d64d51 -r e92153ed8bdc src/hotspot/share/gc/z/zLock.inline.hpp
--- a/src/hotspot/share/gc/z/zLock.inline.hpp	Mon Nov 25 12:22:13 2019 +0100
+++ b/src/hotspot/share/gc/z/zLock.inline.hpp	Mon Nov 25 12:30:24 2019 +0100
@@ -53,7 +53,7 @@
 
   if (owner != thread) {
     _lock.lock();
-    Atomic::store(thread, &_owner);
+    Atomic::store(&_owner, thread);
   }
 
   _count++;
@@ -66,7 +66,7 @@
   _count--;
 
   if (_count == 0) {
-    Atomic::store((Thread*)NULL, &_owner);
+    Atomic::store(&_owner, (Thread*)NULL);
     _lock.unlock();
   }
 }