--- old/src/share/vm/utilities/taskqueue.hpp	2014-08-05 14:39:29.772614508 +0200
+++ new/src/share/vm/utilities/taskqueue.hpp	2014-08-05 14:39:29.554021192 +0200
@@ -331,7 +331,7 @@
     //            index, &_elems[index], _elems[index]);
     E* t = (E*)&_elems[index];      // cast away volatility
     oop* p = (oop*)t;
-    assert((*t)->is_oop_or_null(), "Not an oop or null");
+    assert((*t)->is_oop_or_null(), err_msg("Not an oop or null: " PTR_FORMAT, p2i(*t)));
     f->do_oop(p);
   }
   // tty->print_cr("END OopTaskQueue::oops_do");