--- old/src/share/vm/gc/cms/concurrentMarkSweepGeneration.cpp	2016-09-20 14:24:03.466496214 +0200
+++ new/src/share/vm/gc/cms/concurrentMarkSweepGeneration.cpp	2016-09-20 14:24:03.362496210 +0200
@@ -7829,7 +7829,7 @@
   assert(stack->isEmpty(), "Expected precondition");
   assert(stack->capacity() > num, "Shouldn't bite more than can chew");
   size_t i = num;
-  oop  cur = _overflow_list;
+  oop  cur = oop(_overflow_list);
   const markOop proto = markOopDesc::prototype();
   NOT_PRODUCT(ssize_t n = 0;)
   for (oop next; i > 0 && cur != NULL; cur = next, i--) {
@@ -7840,7 +7840,7 @@
     assert(res, "Bit off more than can chew?");
     NOT_PRODUCT(n++;)
   }
-  _overflow_list = cur;
+  _overflow_list = (oopDesc*)cur;
 #ifndef PRODUCT
   assert(_num_par_pushes >= n, "Too many pops?");
   _num_par_pushes -=n;
@@ -7935,7 +7935,7 @@
     // we left it in a short while ago; in that case we may be
     // able to place back the suffix without incurring the cost
     // of a walk down the list.
-    oop observed_overflow_list = _overflow_list;
+    oop observed_overflow_list = oop(_overflow_list);
     oop cur_overflow_list = observed_overflow_list;
     bool attached = false;
     while (observed_overflow_list == BUSY || observed_overflow_list == NULL) {
@@ -7954,7 +7954,7 @@
       oop suffix_tail = cur;
       assert(suffix_tail != NULL && suffix_tail->mark() == NULL,
              "Tautology");
-      observed_overflow_list = _overflow_list;
+      observed_overflow_list = oop(_overflow_list);
       do {
         cur_overflow_list = observed_overflow_list;
         if (cur_overflow_list != BUSY) {
@@ -7997,7 +7997,7 @@
   assert(p->is_oop(), "Not an oop");
   preserve_mark_if_necessary(p);
   p->set_mark((markOop)_overflow_list);
-  _overflow_list = p;
+  _overflow_list = (oopDesc*)p;
 }
 
 // Multi-threaded; use CAS to prepend to overflow list
@@ -8005,7 +8005,7 @@
   NOT_PRODUCT(Atomic::inc_ptr(&_num_par_pushes);)
   assert(p->is_oop(), "Not an oop");
   par_preserve_mark_if_necessary(p);
-  oop observed_overflow_list = _overflow_list;
+  oop observed_overflow_list = oop(_overflow_list);
   oop cur_overflow_list;
   do {
     cur_overflow_list = observed_overflow_list;
--- old/src/share/vm/gc/cms/concurrentMarkSweepGeneration.hpp	2016-09-20 14:24:04.194496247 +0200
+++ new/src/share/vm/gc/cms/concurrentMarkSweepGeneration.hpp	2016-09-20 14:24:04.094496242 +0200
@@ -540,7 +540,7 @@
 
   // Overflow list of grey objects, threaded through mark-word
   // Manipulated with CAS in the parallel/multi-threaded case.
-  oop _overflow_list;
+  oopDesc* volatile _overflow_list;
   // The following array-pair keeps track of mark words
   // displaced for accommodating overflow list above.
   // This code will likely be revisited under RFE#4922830.
--- old/src/share/vm/gc/cms/parNewGeneration.cpp	2016-09-20 14:24:04.862496276 +0200
+++ new/src/share/vm/gc/cms/parNewGeneration.cpp	2016-09-20 14:24:04.754496272 +0200
@@ -1286,7 +1286,7 @@
       listhead->forward_to(from_space_obj);
       from_space_obj = listhead;
     }
-    oop observed_overflow_list = _overflow_list;
+    oop observed_overflow_list = oop(_overflow_list);
     oop cur_overflow_list;
     do {
       cur_overflow_list = observed_overflow_list;
@@ -1386,7 +1386,7 @@
     // It's possible that the list is still in the empty(busy) state
     // we left it in a short while ago; in that case we may be
     // able to place back the suffix.
-    oop observed_overflow_list = _overflow_list;
+    oop observed_overflow_list = oop(_overflow_list);
     oop cur_overflow_list = observed_overflow_list;
     bool attached = false;
     while (observed_overflow_list == BUSY || observed_overflow_list == NULL) {
@@ -1405,7 +1405,7 @@
         last = last->list_ptr_from_klass();
       }
       // Atomically prepend suffix to current overflow list
-      observed_overflow_list = _overflow_list;
+      observed_overflow_list = oop(_overflow_list);
       do {
         cur_overflow_list = observed_overflow_list;
         if (cur_overflow_list != BUSY) {
--- old/src/share/vm/gc/cms/parNewGeneration.hpp	2016-09-20 14:24:05.522496306 +0200
+++ new/src/share/vm/gc/cms/parNewGeneration.hpp	2016-09-20 14:24:05.414496301 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -323,7 +323,7 @@
   // A list of from-space images of to-be-scanned objects, threaded through
   // klass-pointers (klass information already copied to the forwarded
   // image.)  Manipulated with CAS.
-  oop _overflow_list;
+  oopDesc* volatile _overflow_list;
   NOT_PRODUCT(ssize_t _num_par_pushes;)
 
   // This closure is used by the reference processor to filter out
@@ -383,7 +383,7 @@
   NOT_PRODUCT(bool should_simulate_overflow();)
 
   // Accessor for overflow list
-  oop overflow_list() { return _overflow_list; }
+  oop overflow_list() { return oop(_overflow_list); }
 
   // Push the given (from-space) object on the global overflow list.
   void push_on_overflow_list(oop from_space_obj, ParScanThreadState* par_scan_state);