--- 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, 2012, 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

@@ -84,7 +85,8 @@

                out.print("----------------- ");

                out.print(th);

                out.println(" -----------------");

-               while (f != null) {

+               int maxStack = 256;

+               while (f != null && maxStack-- > 0) {

                   ClosestSymbol sym = f.closestSymbolToPC();

                   Address pc = f.pc();

                   out.print(pc + "\t");

@@ -158,10 +160,19 @@

                         printUnknown(out);

                      }

                   }

+                  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 (isJava && concurrentLocks) {