--- old/src/share/vm/runtime/vmThread.cpp	2013-02-12 14:33:45.132829600 +0100
+++ new/src/share/vm/runtime/vmThread.cpp	2013-02-12 14:33:44.836429100 +0100
@@ -386,7 +386,9 @@
       event.set_operation(op->type());
       event.set_safepoint(op->evaluate_at_safepoint());
       event.set_blocking(!op->evaluate_concurrently());
-      event.set_caller(op->calling_thread()->osthread()->thread_id());
+      // Only write caller thread information for non-concurrent vm operations.
+      // For concurrent vm operations, the caller thread could have exited already.
+      event.set_caller(op->evaluate_concurrently() ? 0 : op->calling_thread()->osthread()->thread_id());
       event.commit();
     }