--- old/src/share/vm/services/memRecorder.cpp	Fri Jul 13 08:04:35 2012
+++ new/src/share/vm/services/memRecorder.cpp	Fri Jul 13 08:04:33 2012
@@ -45,11 +45,11 @@
 }
 
 
-debug_only(volatile jint MemRecorder::_instance_count = 0;)
+volatile jint MemRecorder::_instance_count = 0;
 
 MemRecorder::MemRecorder() {
   assert(MemTracker::is_on(), "Native memory tracking is off");
-  debug_only(Atomic::inc(&_instance_count);)
+  Atomic::inc(&_instance_count);
   debug_only(set_generation();)
 
   if (MemTracker::track_callsite()) {
@@ -83,9 +83,7 @@
     delete _next;
   }
 
-#ifdef ASSERT
   Atomic::dec(&_instance_count);
-#endif
 }
 
 // Sorting order:
--- old/src/share/vm/services/memRecorder.hpp	Fri Jul 13 08:04:41 2012
+++ new/src/share/vm/services/memRecorder.hpp	Fri Jul 13 08:04:40 2012
@@ -249,9 +249,9 @@
 
   SequencedRecordIterator pointer_itr();
 
- public:
+ protected:
   // number of MemRecorder instance
-  debug_only(static volatile jint _instance_count;)
+  static volatile jint _instance_count;
 
  private:
   // sorting function, sort records into following order
--- old/src/share/vm/services/memTrackWorker.hpp	Fri Jul 13 08:04:47 2012
+++ new/src/share/vm/services/memTrackWorker.hpp	Fri Jul 13 08:04:46 2012
@@ -67,7 +67,7 @@
   NOT_PRODUCT(int _last_gen_in_use;)
 
   inline int generations_in_use() const {
-    return (_tail <= _head ? (_head - _tail + 1) : (MAX_GENERATIONS - (_tail - _head) + 1));
+    return (_tail >= _head ? (_tail - _head + 1) : (MAX_GENERATIONS - (_head - _tail) + 1));
   }
 };
 
--- old/src/share/vm/services/memTracker.cpp	Fri Jul 13 08:04:54 2012
+++ new/src/share/vm/services/memTracker.cpp	Fri Jul 13 08:04:52 2012
@@ -361,6 +361,10 @@
       // VM state, so it can stop at safepoint. JavaThread running in VM state does not
       // need lock to write records.
       if (thread->is_Java_thread() && ((JavaThread*)thread)->is_safepoint_visible()) {
+        assert(!(SafepointSynchronize::is_at_safepoint() && 
+          ((JavaThread*)thread)->thread_state() == _thread_blocked),
+           "_thread_blocked allocate/deallocation memory at safepoint");
+
         if (((JavaThread*)thread)->thread_state() == _thread_in_native) {
           ThreadInVMfromNative trans((JavaThread*)thread);
           create_record_in_recorder(addr, flags, size, pc, thread);
@@ -486,8 +490,6 @@
 
   // now, it is the time to shut whole things off
   if (_state == NMT_final_shutdown) {
-    _tracking_level = NMT_off;
-
     // walk all JavaThreads to delete all recorders
     SyncThreadRecorderClosure stc;
     Threads::threads_do(&stc);
@@ -499,8 +501,16 @@
         _global_recorder = NULL;
       }
     }
-
-    _state = NMT_shutdown;
+    MemRecorder* pending_recorders = get_pending_recorders();
+    if (pending_recorders != NULL) {
+      delete pending_recorders;
+    }
+    // wait until MemRecorder instance drops to zero to
+    // completely shutdown NMT
+    if (MemRecorder::_instance_count == 0) {
+      _state = NMT_shutdown;
+      _tracking_level = NMT_off;
+    }
   }
 }