--- old/src/share/vm/gc/g1/g1ConcurrentMark.cpp	2016-09-14 14:48:25.145527455 +0200
+++ new/src/share/vm/gc/g1/g1ConcurrentMark.cpp	2016-09-14 14:48:24.996522844 +0200
@@ -241,8 +241,11 @@
 
 G1CMMarkStack::OopChunk* G1CMMarkStack::remove_chunk_from_chunk_list() {
   MutexLockerEx x(MarkStackChunkList_lock, Mutex::_no_safepoint_check_flag);
-  _chunks_in_chunk_list--;
-  return remove_chunk_from_list(&_chunk_list);
+  OopChunk* result = remove_chunk_from_list(&_chunk_list);
+  if (result != NULL) {
+    _chunks_in_chunk_list--;
+  }
+  return result;
 }
 
 G1CMMarkStack::OopChunk* G1CMMarkStack::remove_chunk_from_free_list() {
@@ -270,7 +273,7 @@
 
 bool G1CMMarkStack::par_push_chunk(oop* ptr_arr) {
   // Get a new chunk.
-  OopChunk* new_chunk = remove_chunk_from_list(&_free_list);
+  OopChunk* new_chunk = remove_chunk_from_free_list();
 
   if (new_chunk == NULL) {
     // Did not get a chunk from the free list. Allocate from backing memory.
@@ -284,24 +287,21 @@
 
   Copy::conjoint_oops_atomic(ptr_arr, new_chunk->data, OopsPerChunk);
 
-  add_chunk_to_list(&_chunk_list, new_chunk);
-  Atomic::inc(&_chunks_in_chunk_list);
+  add_chunk_to_chunk_list(new_chunk);
 
   return true;
 }
 
 bool G1CMMarkStack::par_pop_chunk(oop* ptr_arr) {
-  OopChunk* cur = remove_chunk_from_list(&_chunk_list);
+  OopChunk* cur = remove_chunk_from_chunk_list();
 
   if (cur == NULL) {
     return false;
   }
 
-  Atomic::dec(&_chunks_in_chunk_list);
-
   Copy::conjoint_oops_atomic(cur->data, ptr_arr, OopsPerChunk);
 
-  add_chunk_to_list(&_free_list, cur);
+  add_chunk_to_free_list(cur);
   return true;
 }