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Date: Fri, 22 Jun 2007 14:59:26 -0700 (PDT)
From: "Rana Dasgupta (JIRA)" <jira@apache.org>
To: commits@harmony.apache.org
Subject: [jira] Commented: (HARMONY-3627) [drlvm][exception] VM works
 incorrectly if several threads catch StackOverflowError
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    [ https://issues.apache.org/jira/browse/HARMONY-3627?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12507528 ] 

Rana Dasgupta commented on HARMONY-3627:
----------------------------------------

It seems to me that when this test is run with many threads and multiple times, sometimes ( even during clean exit ) the stack guard state does not get get restored correctly. So the stack area is left unguarded and next time the stack overflows into the unmapped area at the bottom of the stack. I don't think that think that this type of access violation is catchable because NT treats it as a fatal error and tears down the process. 

We can test this out by putting a debug BP or some trace messages in asm_exception_catch_callback to ensure that the guard is getting reset. I don't have time to try this out right now, sorry.

> [drlvm][exception] VM works incorrectly if several threads catch StackOverflowError
> -----------------------------------------------------------------------------------
>
>                 Key: HARMONY-3627
>                 URL: https://issues.apache.org/jira/browse/HARMONY-3627
>             Project: Harmony
>          Issue Type: Bug
>          Components: DRLVM
>            Reporter: Vera Petrashkova
>            Priority: Minor
>
> When several threads expect  StackOverflowError then VM works incorrectly.
> The following test demonstrates this issue.
> VM crashes or finish its run abnormally.
> ----------------test.java-------------------
> public class test extends Thread {
>    public static void main (String[] argv) {
>         int N_TH = 5;
>         try {
>             if (argv.length > 0) {
>                 N_TH=Integer.parseInt(argv[0]);
>             }
>         } catch (Throwable e) {
>         }
>         test t[] = new test[N_TH];
>         for (int i = 0; i < N_TH; i++) {
>             t[i]=new test();
>             t[i].start();
>         }
>         try {
>             for (int i = 0; i < N_TH; i++) {
>                 t[i].join();
>             }
>         } catch (Throwable e) {
>             System.err.println(e);
>         }
>         System.out.println("Test passed");
>     }
>     public void m(int t) {
>              m(t+1);
>     }
>     public void run() {
>         System.err.println("Start");
>         try {
>             m(0);
>         } catch (StackOverflowError e) {
>         }
>     }
> }
> ------------------------------
> Run test
> java  -cp . test 20
> Output:
> Sometimes test passes.
> Apache Harmony Launcher : (c) Copyright 1991, 2006 The Apache Software Foundation or its l
> icensors, as applicable.
> java version "1.5.0"
> pre-alpha : not complete or compatible
> svn = r526746, (Apr 10 2007), Windows/ia32/msvc 1310, release build
> http://incubator.apache.org/harmony
> Start
> ...
> Start
> Test passed
> But  usually VM does not report full message and finishes execution or crashes:
> Start
> Start
> Start

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