--- a/src/hotspot/share/runtime/mutexLocker.hpp	Mon Jun 11 15:28:24 2018 +0200
+++ b/src/hotspot/share/runtime/mutexLocker.hpp	Fri Jun 15 00:49:54 2018 -0700
@@ -130,6 +130,7 @@
 extern Monitor* Service_lock;                    // a lock used for service thread operation
 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
 extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
+extern Mutex*   ThreadHeapSampler_lock;          // protects the static data for initialization.
 
 #if INCLUDE_JFR
 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table