src/hotspot/share/gc/g1/heapRegionManager.cpp

@@ -318,11 +318,11 @@
   // entry which is either free or not yet committed.  If not yet
   // committed, expand_at that index.
   uint curr = max_length() - 1;
   while (true) {
     HeapRegion *hr = _regions.get_by_index(curr);
-    if (hr == NULL) {
+    if (hr == NULL || !is_available(curr)) {
       uint res = expand_at(curr, 1, NULL);
       if (res == 1) {
         *expanded = true;
         return curr;
       }