diff a/src/hotspot/share/runtime/os.cpp b/src/hotspot/share/runtime/os.cpp
--- a/src/hotspot/share/runtime/os.cpp
+++ b/src/hotspot/share/runtime/os.cpp
@@ -794,11 +794,11 @@
   }
   return ptr;
 #endif
 }
 
-
+// handles NULL pointers
 void  os::free(void *memblock) {
   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 #ifdef ASSERT
   if (memblock == NULL) return;
   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {