--- a/src/hotspot/share/classfile/classLoaderDataGraph.hpp	Thu Jun 06 20:19:03 2019 +0200
+++ b/src/hotspot/share/classfile/classLoaderDataGraph.hpp	Thu Jun 06 15:09:17 2019 -0400
@@ -41,7 +41,7 @@
   friend class VMStructs;
  private:
   // All CLDs (except the null CLD) can be reached by walking _head->_next->...
-  static ClassLoaderData* _head;
+  static ClassLoaderData* volatile _head;
   static ClassLoaderData* _unloading;
   // CMS support.
   static ClassLoaderData* _saved_head;