--- a/hotspot/src/share/vm/gc/shared/workgroup.hpp	Tue Sep 20 00:34:54 2016 +0000
+++ b/hotspot/src/share/vm/gc/shared/workgroup.hpp	Tue Sep 20 11:41:43 2016 +0200
@@ -318,9 +318,9 @@
 // enumeration type.
 
 class SubTasksDone: public CHeapObj<mtInternal> {
-  uint* _tasks;
+  volatile uint* _tasks;
   uint _n_tasks;
-  uint _threads_completed;
+  volatile uint _threads_completed;
 #ifdef ASSERT
   volatile uint _claimed;
 #endif
@@ -363,11 +363,11 @@
 class SequentialSubTasksDone : public StackObj {
 protected:
   uint _n_tasks;     // Total number of tasks available.
-  uint _n_claimed;   // Number of tasks claimed.
+  volatile uint _n_claimed;   // Number of tasks claimed.
   // _n_threads is used to determine when a sub task is done.
   // See comments on SubTasksDone::_n_threads
   uint _n_threads;   // Total number of parallel threads.
-  uint _n_completed; // Number of completed threads.
+  volatile uint _n_completed; // Number of completed threads.
 
   void clear();