--- old/src/hotspot/share/runtime/mutexLocker.hpp	2017-10-06 14:50:13.410632486 -0700
+++ new/src/hotspot/share/runtime/mutexLocker.hpp	2017-10-06 14:50:13.018633806 -0700
@@ -125,6 +125,8 @@
 extern Monitor* PeriodicTask_lock;               // protects the periodic task structure
 extern Monitor* RedefineClasses_lock;            // locks classes from parallel redefinition
 
+extern Monitor* HeapMonitor_lock;                // protects internal storage in HeapMonitoring
+
 #if INCLUDE_TRACE
 extern Mutex*   JfrStacktrace_lock;              // used to guard access to the JFR stacktrace table
 extern Monitor* JfrMsg_lock;                     // protects JFR messaging