--- old/src/hotspot/share/trace/tracingExport.hpp	2018-04-02 10:09:46.000000000 -0400
+++ new/src/hotspot/share/trace/tracingExport.hpp	2018-04-02 10:09:46.000000000 -0400
@@ -29,11 +29,11 @@
 
 class TracingExport : AllStatic {
  public:
-  static Thread * get_sampler_thread();
-  static void set_sampler_thread(Thread * thread);
+  static Thread* get_sampler_thread();
+  static void set_sampler_thread(Thread* thread);
 
  private:
-  static Thread * _sampler_thread;
+  static Thread* volatile _sampler_thread;
 };
 
 #endif // SHARE_VM_TRACE_TRACINGEXPORT_HPP