diff -r 4547f8303f2d -r bc5c7f63dbae src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp
--- a/src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp	Thu Nov 08 12:24:08 2018 +0100
+++ b/src/hotspot/share/jfr/periodic/sampling/jfrThreadSampler.cpp	Thu Nov 08 07:42:08 2018 -0500
@@ -321,7 +321,6 @@
   int _cur_index;
   const u4 _max_frames;
   volatile bool _disenrolled;
-  static Monitor* _transition_block_lock;
 
   JavaThread* next_thread(ThreadsList* t_list, JavaThread* first_sampled, JavaThread* current);
   void task_stacktrace(JfrSampleType type, JavaThread** last_thread);
@@ -339,12 +338,10 @@
 
  public:
   void run();
-  static Monitor* transition_block() { return _transition_block_lock; }
+  static Monitor* transition_block() { return JfrThreadSampler_lock; }
   static void on_javathread_suspend(JavaThread* thread);
 };
 
-Monitor* JfrThreadSampler::_transition_block_lock = new Monitor(Mutex::leaf, "Trace block", true, Monitor::_safepoint_check_never);
-
 static void clear_transition_block(JavaThread* jt) {
   jt->clear_trace_flag();
   JfrThreadLocal* const tl = jt->jfr_thread_local();