--- old/src/hotspot/share/utilities/lockFreeStack.hpp	2019-11-21 11:54:20.796117507 +0100
+++ new/src/hotspot/share/utilities/lockFreeStack.hpp	2019-11-21 11:54:20.536113109 +0100
@@ -103,7 +103,7 @@
   // list of elements.  Acts as a full memory barrier.
   // postcondition: empty()
   T* pop_all() {
-    return Atomic::xchg((T*)NULL, &_top);
+    return Atomic::xchg(&_top, (T*)NULL);
   }
 
   // Atomically adds value to the top of this stack.  Acts as a full