###@###.### 04/15/2002

The test case below results in a hotspot crash when run with
java_g -XX:+CheckMemoryInitialization. Reproducible with the
most recent 1.4.1 build: 1.4.1 beta-b08-debug, solaris 7

Description from HP:
===================

To reproduce compile and run:

import java.io.*;
public class TestGC64
{
  static byte[] mybuf = new byte[15000];
  static int counter = 0;
  static void doWrite()
  {
    ++ counter;
    //mybuf = new byte[15000000]; mybuf = new byte[15000000]; mybuf = null;
    //while (true) {
        //mybuf = new byte[15000]; mybuf = new byte[15000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        mybuf = new byte[15000000]; mybuf = null;
        //System.out.print("x ");
        System.err.print(counter + " ");
    //}
    doWrite();
  }
  public static void main(String[] args)
  {
    try { System.gc(); doWrite(); }
    catch (java.lang.StackOverflowError e3)
    { System.out.println("WORKED"); }
  }
}


Most of the code not having direct impact have been commented out. Infact I was able to reproduce the problem with just a System.gc() in the program and nothing else.

I get the following abort.

--------------------------------------------------------------------
VM option '+CheckMemoryInitialization'
VM option '+ZapUnusedHeapArea'
#
# HotSpot Virtual Machine Error, assertion failure
# Please report this error at
# http://java.sun.com/cgi-bin/bugreport.cgi
#
# Java VM: Java HotSpot(TM) Client VM (1.4.0-b92-debug mixed mode)
#
# assert((*(intptr_t*) (result + slot)) == ((intptr_t) badHeapWordVal), "initialized memory")
#
# Error ID: /export/home3/jdk/jdk1.4/ws/hotspot/src/share/vm/memory/collectedHeap.inline.hpp, 93 [ Patched ]
#
# Problematic Thread: prio=5 tid=0x3d580 nid=0x1 runnable
#
Dumping core....
--------------------------------------------------------------------

Initially I ran into this problem with 64 bit and verified that 32 bit fails too.

badHeapWordVal is defined as 0xBAADBABE in globalDefinitions.hpp.
But for 64 bit mode it should be 0xBAADBABEBAADBABE. I fixed this place and execution continued and hit another similar assert.