--- openjdk/hotspot/agent/src/share/classes/sun/jvm/hotspot/tools/PStack.java	2012-04-06 02:26:33.322164601 +0200
+++ openjdk/hotspot/agent/src/share/classes/sun/jvm/hotspot/tools/PStack.java	2012-04-06 02:26:57.958514071 +0200
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, Red Hat Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -158,10 +160,19 @@
                          }
                       }
                   }
+                  Address oldPC = f.pc();
+                  Address oldFP = f.localVariableBase();
                   f = f.sender(th);
+                  if (f != null
+                      && oldPC.equals(f.pc())
+                      && oldFP.equals(f.localVariableBase())) {
+                      // We didn't make any progress
+                      f = null;
+                  }
                }
             } catch (Exception exp) {
-               exp.printStackTrace();
+               // exp.printStackTrace();
+               out.println("bad stack: " + exp);
                // continue, may be we can do a better job for other threads
             }
             if (concurrentLocks) {