CHESS – Find and Reproduce Concurrency Heisenbugs Forum

Help in deciphering stack track created by chess

Sun, 29 Nov 2009 20:48:25 Z

First of all, thank you for a great tool. I really like Chess! As a future request, support log4net and by that I mean the deprecated ReadWriteLock or at least avoid instrumenting log4net by default (I know I should look at how to avoid instrumenting assemblies, but still, it would be nice)

Alright, trying to debug a work stealing queue taken from here:
http://www.bluebytesoftware.com/blog/2008/08/12/BuildingACustomThreadPoolSeriesPart2AWorkStealingQueue.aspx

I've added the changes recommended by this crazy awesome russian:
http://groups.google.com/group/relacy/browse_frm/thread/f91c913c298a20ab

And now I figured I'd test chess on it.

Here's the code: http://www.copypastecode.com/16429/

Here's my test case: http://www.copypastecode.com/16433/

And here's the stack:

Microsoft.ExtendedReflection.dll!Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break(string message) + 0x78 bytes	

Microsoft.ExtendedReflection.dll!Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break() + 0x8 bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.ClrSyncManager.DebugBreak() + 0x1b bytes	

Microsoft.ManagedChess.MChess.dll!<Module>.Microsoft.ManagedChess.ShimSyncManager.DebugBreak() + 0x73 bytes	

[Native to Managed Transition]	

[Managed to Native Transition]	

Microsoft.ManagedChess.MChess.dll!Microsoft.ManagedChess.MChessChess.SyncVarAccess(int var = 512, MSyncVarOp op = RWVAR_WRITE) + 0x2c bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.Conversions.SyncVarAccess(int varnum = 512, MSyncVarOp op = RWVAR_WRITE) + 0x16e bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.ClrSyncManager.SyncVarAccess(Microsoft.ExtendedReflection.Monitoring.GCAddress o = {Microsoft.ExtendedReflection.Monitoring.GCAddress}, MSyncVarOp mop = RWVAR_WRITE) + 0x4f bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.ClrSyncManager.raw_access(System.UIntPtr address = 45707496, uint size = 4, bool volatile = true, bool write = true) + 0x19a bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.ClrSyncManager.ObjectAccessThreadMonitor_WriteAccess(System.UIntPtr address = 45707496, uint size = 4, bool volatile = true) + 0x2f bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.CallsOnly.ObjectAccessThreadMonitor.Store(System.UIntPtr interiorPointer = 45707496, uint size = 4, bool volatile = true) + 0x43 bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.CallsOnly.ThreadMonitorFactory.Store(System.UIntPtr location = 45707496, uint size = 4, bool volatile = true) + 0x94 bytes	

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.AllCallbacks.ThreadExecutionMonitorDispatcher.Store(System.UIntPtr location = 45707496, uint size = 4, bool is_volatile = true) + 0x5c bytes	

Microsoft.ExtendedReflection.dll!Microsoft.ExtendedReflection.Monitoring.ThreadExecutionMonitorMultiplexer.Microsoft.ExtendedReflection.Monitoring.IThreadExecutionMonitor.Store(System.UIntPtr location = 45707496, uint size = 4, bool volatile = true) + 0x63 bytes	

Microsoft.ExtendedReflection.dll!Microsoft.ExtendedReflection.Monitoring._Addresses.StoreVolatile(System.UIntPtr location, uint size) + 0x48 bytes	

Core.dll!Core.Threading.WorkStealingQueue<int>.LocalPush(int obj = 3) Line 52 + 0x3b bytes	C#

tests.concurrent.dll!Tests.Concurrent.WorkStealingQueueTests.OneProdOneCons.AnonymousMethod() Line 83 + 0x17 bytes	C#

Microsoft.ManagedChess.Engine.dll!Microsoft.ManagedChess.EREngine.Helper.WrapThreadStart.AnonymousMethod() + 0x64 bytes	

mscorlib.dll!System.Threading.ThreadHelper.ThreadStart_Context(object state) + 0x65 bytes	

mscorlib.dll!System.Threading.ExecutionContext.runTryCode(object userData) + 0x52 bytes	

[Native to Managed Transition]	

[Managed to Native Transition]	

mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0xc4 bytes	

mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x69 bytes	

mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x41 bytes

The line it breaks on is `_TailIndex = tail + 1;` inside LocalPush(T t).

development schedule?

Sun, 29 Nov 2009 20:03:59 Z

Is there any ballpark date for when MCHESS and the Concurrency Explorer may get rolled into the VS.NET IDE?

Can't open Concurrency Explorer from ChessBoard

Wed, 18 Nov 2009 15:18:10 Z

Hi,

I tried the race condition sample, and did "repo result with trace" in ChessBoard, but when I right click on the race results once it's completed, I do not see the "open with concurrency explorer" option. Am I missing something?

At the same time when i run mchess with "/detectraces /alltraces" and then second time with /ls option as "/detectraces /alltraces /ls" I see ConcurrencyExplorer works can read trace file correctly. Not sure though what does /ls command do (was prompted to run with /ls option which is undocumented) and why we need to run mchess twice?

Please correct me if i am wrong.

Thanks,

Rohit

Bugs with two ore more preemption

Wed, 18 Nov 2009 11:25:55 Z

Hello!
First of all I want to thank CHESS developers and researchers for practical oriented research and for applying the results in industry.
I'm trying to understand the nature of concurrent bugs and classification of bugs by the required number of preemptions seems promising to me. I want to start with analysis of bugs in real industrial apllications, especially bugs with two ore more preemptions. I've read the CHESS papers and found that it was applied to PLINQ, Singularity, Transaction Manager, Dryad, CCR and etc. But there is little information about bugs with more than one preemption. I found only one description of bug in CCR with two context switches in the article "Finding and Reproducing Heisenbugs in Concurrent Programs". Example with workers A,B. "Worker A registers to process a set of tasks in a port while a worker B cancels all the tasks in the port." Unfortunately I didn't understand how the code in the implementation should look like to get this bug and why we need at least two preemptions? How the test driver looks like?
Also, if it is possible I would appreciate if you could share bugs with two or more preemptions found in the other programs.

Can chess work with Boost API?

Thu, 07 May 2009 16:24:03 Z

We are using boost threading and synchronization API in our source code. I think that boost API are just wrapping the win32 API on win32 platforms.

BTW, where can I find the CHESS "user manual"?

Thanks a lot!
Sean

This test passes in Visual Studio but fails in ChessBoard

Thu, 12 Nov 2009 19:41:59 Z

This test passes in Visual Studio:

But fails in ChessBoard:

It appears that when run with ChessBoard, BaseClass.TestInitialize() is not called. Is this a bug?

Share stories of CHESS wins/losses

Thu, 15 Jan 2009 20:57:57 Z

Are you using CHESS? Do you have success or horror stories to share? We would love to hear about how CHESS works in the field. Use this thread to share your experiences about CHESS.

Thanks, the CHESS team.

CHESS and .NET 4.0/Parallel Extensions

Thu, 13 Aug 2009 09:21:34 Z

Hi,

just wonder if you have any plans for CHESS regarding .Net 4.0/Parallel Extensions?

Thanks
Daniel

Troubleshooting the /includeassembly option.

Wed, 21 Oct 2009 23:53:58 Z

A few different times I've run into the situation where I've tried to include assemblies (or namespaces) to mchess, but mchess appears to not be able to actually include the assembly. Mainly I've suspected this because in deadlock situations mchess says that the execution times out or only one test or schedule is explored in another multithreaded test case. Unfortunately, mchess doesn't say a word if an assembly name is supplied that it doesn't recognize (e.g., /ia:FakeName), so there's no feedback for troubleshooting beyond that.

The test project I'm using is in a solution with the assembly I'm trying to include, and everything is building correctly, so I'm assuming all of the project references are setup correctly. Are there any tips to move on from here? I've only noticed this a handful of times and by playing around I've been usually able to get it, I'm just looking for a better solution.

Thanks!

Livelock... not sure how to solve this.

Thu, 15 Oct 2009 18:08:10 Z

Hi guys. First I want to say how cool Chess is; it's already helped me to refactor a lot of code that had nearly unreproducible concurrency bugs.

Second, I want to ask about this livelock that Chess is detecting. I don't see how this could generate a livelock, nor do I see how I would solve the problem. Maybe I don't understand enough about livelocks to wrap my brain around this problem, but I thought I'd ask your advice anyway.

Here is the code that is showing a livelock... It's basically a wrapper for a generic dictionary. Any help would be greatly appreciated.

public bool TryGetValue(K primaryKey, out V val)
{
	// baseDictionaryLock is a ReadWriterLockSlim
	baseDictionaryLock.EnterReadLock();

	try
	{
		return baseDictionary.TryGetValue(primaryKey, out val);
	}
	finally
	{
		// Chess breaks here saying it has detected livelock
		baseDictionaryLock.ExitReadLock();
	}
}

Debug assertion failed - workaround

Wed, 14 Oct 2009 01:15:37 Z

Regarding: http://social.msdn.microsoft.com/Forums/en-US/chess/thread/56288005-4382-4215-9e56-bcaa99fda117

I had used CHESS a few months back to test some things in our codebase - had found a few issues in the multithreaded code. While testing - I had also found the above issue.

I pulled my old tests today and the error mentioned in the thread seems to occur frequently (I have the latest release of CHESS).

So now I clean and rebuild the solution under test before I run mchess (from commandline or via chessboard) each time and the problem isnt there.

i.e. If I rebuild the solution each time before running mchess the error goes away.

Hope this helps anyone if they run into this problem.

Thanks,
Sriram

Code with no lock statements

Wed, 07 Oct 2009 14:12:52 Z

Currently my code has no lock statements - I want to use CHESS too detect where I need them.

I modified the Account class in the Bank example and removed all the lock statements. This resulted in the chess test passing every time, compared to stress tests which sometimes (very few) discover the bug.

So if I don't have lock statements CHESS won't work?

The following is the code of the account class:

public class Account
{
    private int balance;

    public Account(int amount)
    {
        balance = amount;
    }

    public void Withdraw(int amount)
    {
        balance = balance - amount;
    }

    public int Read()
    {
        return balance;
    }

    public void Deposit(int amount)
    {
        balance = balance + amount;
    }
}

This is the test code:

[TestMethod]
[HostType("Chess")]
public void WithdrawAndDepositConcurrently()
{
    var account = new Account(10);
    var child = new Thread(
       o => { (o as Account).Withdraw(2); }
       );
    child.Start(account);
    account.Deposit(1);
    child.Join();

    Assert.AreEqual<int>(9, account.Read());
}

[TestMethod]
public void WithdrawAndDepositStress10000()
{
    for (int i = 0; i < 10000; i++)
        WithdrawAndDepositConcurrently();
}

[TestMethod]
public void WithdrawAndDepositStress100000()
{
    for (int i = 0; i < 100000; i++)
        WithdrawAndDepositConcurrently();
}

Most of the time, only the last test discovers the bug.

Best Regards,
Walker

ASP.NET Cache Testing Pattern

Wed, 30 Sep 2009 14:45:26 Z

I'd like to use CHESS to test for thread safety amongst my cached objects within my ASP.NET application. I've constructed a few tests but am struggling with confidence that CHESS is really providing any help.

I'd like to know if anyone has a good pattern for testing this that I might be able to compare my tests against?

Is it possible to write a CHESS test that proves that reads and writes of 64-bit values are not atomic on 32-bit systems?

Fri, 11 Sep 2009 04:55:04 Z

Is it possible to write a CHESS test that proves that reads and writes of 64-bit values are not atomic on 32-bit systems?

Why does this test pass instead of say "Detected nondeterminism outside the control of CHESS"?

Tue, 01 Sep 2009 06:49:24 Z

Why does this test pass instead of say "Detected nondeterminism outside the control of CHESS"?

Error Running mchess

Mon, 31 Aug 2009 21:31:23 Z

I ran my exe with mchess in the following way mchess Controller.exe

Here is the error:

ManagedCHESS. Copyright (C) Microsoft Corporation, 2008.
Analyzing Controller.exe ...

***************** CHESS assertion ***********************
Error: could not find class ChessTest

Why does this test with an instance int pass but this test with a static int fail?

Sun, 30 Aug 2009 20:53:40 Z

Why does this test with an instance int pass but this test with a static int fail?

What is Visual Studio Database Edition?

Tue, 25 Aug 2009 18:30:03 Z

What is the differantial of GDR and 9.0 VSDB edition?

Increase the timeout in chess

Tue, 25 Aug 2009 19:54:23 Z

My test method takes 2 minutes to execute. Is there a way to increase the timeout to 2 minutes when running with Chess?

How to fix "(file not found)" in ChessBoard?

Sat, 22 Aug 2009 17:04:48 Z

In ChessBoard when I try to run any test, I receive a "(file not found)" error:

How can this be fixed?

How do you specify /detectraces+ and /preemptaccesses+ with attributes?

Fri, 21 Aug 2009 23:50:48 Z

How do you specify /detectraces+ and /preemptaccesses+ with attributes?

I found [TestProperty("ChessMonitorVolatiles", "true")] in a forum post for /volatile+ but I haven't found attributes for /detectraces+ and /preemptaccesses+.

Is there a list of all CHESS attributes?

Why does this blank unit test with [HostType("Chess")] fail?

Wed, 19 Aug 2009 22:46:23 Z

Why does this blank unit test with [HostType("Chess")] fail?

concurrencyexplorer - no information available

Tue, 07 Jul 2009 17:16:43 Z

Hi,

I would like to see the execution trace using concurrency explorer, but the thread pane display displays "no information available". As far as I can tell, the sourcefile is compiled to produce debugging information:

cl /LDd /nologo /EHsc /Zi /Oi /MDd /Gm- /W4 /Gs /D_X86_ /Fefig2.fixed.asplos08.dll /Fdfig2.fixed.asplos08.pdb fig2.fixed.asplos08.cpp /link /machine:x86 /debug /debugtype:cv,fixup /release /incremental:no /subsystem:console fig2.fixed.asplos08.cpp
..\..\bin\wchess.exe /trace fig2.fixed.asplos08.dll
..\..\bin\concurrencyexplorer.exe trace

Could you please tell me if there is something I'm doing wrong? Btw, how is concurrencyexplorer supposed to know where is the debugging information, the file "trace" created by wchess does not contain any pointer to the c/object input files.

Thank you for help! (sorry for the naive question :)
Corneliu

CHESS detected livelock -- but no information

Thu, 05 Mar 2009 19:47:02 Z

I installed CHESS today and set up a unit test covering a pretty basic scenario (spins up a couple threads simulating multiple incoming connections that we need to respond to) and configured it to run under CHESS. When I run it, it reports a failure and the error message is "CHESS detected livelock". That's it. There's no console information, no further info of any sort. I tried setting the test params as follows:

[TestMethod]

[HostType("Chess")]

[TestProperty("ChessDebug", "true")]

[TestProperty("ChessBreak", "livelock")]

public void LoginManyClientsAtOnce()

{

...

}

I try debugging the test or running it, and either way, the result is the same. In the CHESS console window that comes up, I can see that an error or exception of some sort is popping up but the window closes down before I have a chance to read it. If I comment out the CHESS-specific properties to just run the test normally, it runs fine and I get my happy green checkmark. Uncomment those lines and run it through CHESS, and I get that not-so-helpful error...

Any suggestions? Is there any log being written anywhere I could grab? It could easily be something silly like a missing dependency, but I have no way of knowing....

ChessMode Repo -- reports failed but does not break (or give information about break)

Sun, 19 Jul 2009 09:10:54 Z

The test passes w/o HostType("Chess") attribute.
When running the test with HostType("Chess") I get a failure and paste in the additional attributes.
When I rerun, it says "failed", but does not honor the breaks and I get no additional information.

This test relies on a publicized version of the DLL -- could that be an issue?

Also, the concurrency explorer doesn't come up as it did in the PDC session video / demo.

Suggestions?

Cannot pass a GCHandle across AppDomains across AppDomains.Parameter name: handle

Wed, 15 Jul 2009 21:46:40 Z

"Cannot pass a GCHandle across AppDomains across AppDomains" "Parameter name: handle"

Anyone ever get this related to CHESS? There are postings from way back in 2006 but those are regarding TFS and WorkItemStore.. I am using VS 2008 Team Suite with SP1, unit testing with CHESS:

I am implementing Dispose pattern with GC.SupressFinalize... otherwise I am not doing any fancy GC stuff:

" at System.Runtime.InteropServices.GCHandle.InternalCheckDomain(IntPtr handle)\r\n at System.Runtime.InteropServices.GCHandle.FromIntPtr(IntPtr value)\r\n at Microsoft.ManagedChess.ShimSyncManager.Exit(ShimSyncManager* , Int32 code)\r\n at Microsoft.ManagedChess.ShimSyncManager.ChessWaitOrTimerCallback(Void* lpParameter, Byte TimerOrWaitFired)"

Concurrency explorer minor issue

Tue, 16 Jun 2009 21:48:12 Z

Hi,

I am a newbie to CHESS, thought I would test some parts of our codebase for concurrency issues with it.

I am running it on my Windows XP box using virtual PC 2007 SP1.

I wrote a test and ran mchess, and it finds a deadlock (thanks!).

A minor thing I noticed:

1. I open chessboard with chessboard results.xml
2. I repro the test with tracing by right-clicking...
3. Then I try to open concurrency explorer by right clicking from results R1 Found Datarace at add_Changed

However the window opens with an error box and the concurrency explorer in the background keeps flickering with purple and green colors:

(Note in step 3 if I choose E Deadlock, concurrency explorer open fine).

The detailed stack trace in the error box (with heading Concurrency Explorer II) is:

--- Start Error Message ---
See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.ArgumentOutOfRangeException: InvalidArgument=Value of '1' is not valid for 'index'.
Parameter name: index
   at System.Windows.Forms.ListView.ListViewItemCollection.get_Item(Int32 index)
   at Microsoft.ConcurrencyExplorer.MultiThreadView.listView1_ItemChecked(Object sender, ItemCheckedEventArgs e)
   at System.Windows.Forms.ItemCheckedEventHandler.Invoke(Object sender, ItemCheckedEventArgs e)
   at System.Windows.Forms.ListView.OnItemChecked(ItemCheckedEventArgs e)
   at System.Windows.Forms.ListView.WmReflectNotify(Message& m)
   at System.Windows.Forms.ListView.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

************** Loaded Assemblies **************
mscorlib
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///c:/WINDOWS/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll
----------------------------------------
ChessBoard
    Assembly Version: 1.0.0.0
    Win32 Version: 1.0.0.0
    CodeBase: file:///C:/Program%20Files/Microsoft%20CHESS/bin/chessboard.exe
----------------------------------------
System.Windows.Forms
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Drawing
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System.Xml.Linq
    Assembly Version: 3.5.0.0
    Win32 Version: 3.5.30729.1 built by: SP
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Xml.Linq/3.5.0.0__b77a5c561934e089/System.Xml.Linq.dll
----------------------------------------
System.Core
    Assembly Version: 3.5.0.0
    Win32 Version: 3.5.30729.1 built by: SP
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Core/3.5.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
System.Xml
    Assembly Version: 2.0.0.0
    Win32 Version: 2.0.50727.3053 (netfxsp.050727-3000)
    CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
ConcurrencyExplorer
    Assembly Version: 0.1.30610.2
    Win32 Version: 0.1.30610.2
    CodeBase: file:///C:/Program%20Files/Microsoft%20CHESS/bin/ConcurrencyExplorer.EXE
----------------------------------------
Microsoft.ManagedChess.MChess
    Assembly Version: 0.1.30610.2
    Win32 Version:
    CodeBase: file:///C:/Program%20Files/Microsoft%20CHESS/bin/Microsoft.ManagedChess.MChess.DLL
----------------------------------------

************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.

For example:

<configuration>
    <system.windows.forms jitDebugging="true" />
</configuration>

When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.

--- Start Error Message ---

If I dismiss the error enough times, eventually the app crashes with:
Unhandled Exception: System.ComponentModel.Win32Exception: Error creating window
handle.
   at System.Windows.Forms.NativeWindow.CreateHandle(CreateParams cp)
   at System.Windows.Forms.Control.CreateHandle()
   at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
   at System.Windows.Forms.Control.CreateControl()
   at System.Windows.Forms.Control.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.ButtonBase.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.Control.OnParentVisibleChanged(EventArgs e)
   at System.Windows.Forms.Control.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.ScrollableControl.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.Form.OnVisibleChanged(EventArgs e)
   at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
   at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
   at System.Windows.Forms.Control.set_Visible(Boolean value)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 r
eason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason
, ApplicationContext context)
   at System.Windows.Forms.Application.RunDialog(Form form)
   at System.Windows.Forms.Form.ShowDialog(IWin32Window owner)
   at System.Windows.Forms.Form.ShowDialog()
   at System.Windows.Forms.Application.ThreadContext.OnThreadException(Exception
t)
   at System.Windows.Forms.Timer.TimerNativeWindow.OnThreadException(Exception e
)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr
wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.Uns
afeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int3
2 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 r
eason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason
, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at Microsoft.ConcurrencyExplorer.StandardView.RunGuiThread()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, C
ontextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

Thanks,
Sriram

Debugger doesn't launch with /break:s option

Fri, 29 May 2009 10:19:26 Z

Hi team
I had a short email trail with you about this earlier but since the problem is still unresolved I figured I'd post it here.

I ran the BankAccount sample using mchess to see the expected result (returns false). Then, following the instructions in the "bankWithMchess.doc" document, I tried this command:

mchess ChessTest.exe /repro /break:c

This doesn't detect that a debugger is not attached nor does it prompt to attach to a debugger. It outputs a few stack traces (shown below)

Thanks
Amit

ManagedCHESS. Copyright (C) Microsoft Corporation, 2008.
Analyzing ChessTest.exe ...
user breakpoint requested:
   at Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break(String message)
   at Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break()
   at Microsoft.ManagedChess.EREngine.ClrSyncManager.DebugBreak()
   at Microsoft.ManagedChess.ShimSyncManager.DebugBreak(ShimSyncManager* )
   at Chess.SyncVarAccess(UInt32 , UInt32 )
   at Microsoft.ManagedChess.MChessChess.SyncVarAccess(Int32 var, MSyncVarOp op)
   at Microsoft.ManagedChess.EREngine.ClrSyncManager.SyncVarAccess(Object o, MSyncVarOp mop)
   at __Substitutions.System.Threading.Monitor.<>c__DisplayClass2.<TryEnterRaw>b__0(ClrSyncManager manager)
   at Microsoft.ManagedChess.EREngine.Helper.SimpleWrap[T](SimpleDelmanager`1 foo, SimpleDel`1 bar)
   at __Substitutions.System.Threading.Monitor.TryEnterRaw(Object lock, Int32 timeOut, MSyncVarOp operation, String name)
   at __Substitutions.System.Threading.Monitor.Enter(Object lock)
   at Bank.Account.Deposit(Int32 amount)
   at TestBank.ChessTest.Run()
   at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.ManagedChess.EREngine.ChessMain..ctor(MChessOptions m, Assembly a, String tc)
   at Microsoft.ManagedChess.Base.Program.Execute()
   at Microsoft.ManagedChess.Base.Program.Main(String[] args)

user breakpoint requested:
   at Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break(String message)
   at Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break()
   at Microsoft.ManagedChess.EREngine.ClrSyncManager.DebugBreak()
   at Microsoft.ManagedChess.ShimSyncManager.DebugBreak(ShimSyncManager* )
   at Chess.SyncVarAccess(UInt32 , UInt32 )
   at Microsoft.ManagedChess.MChessChess.SyncVarAccess(Int32 var, MSyncVarOp op)
   at Microsoft.ManagedChess.EREngine.ClrSyncManager.SyncVarAccess(Object o, MSyncVarOp mop)
   at __Substitutions.System.Threading.Monitor.<>c__DisplayClass2.<TryEnterRaw>b__0(ClrSyncManager manager)
   at Microsoft.ManagedChess.EREngine.Helper.SimpleWrap[T](SimpleDelmanager`1 foo, SimpleDel`1 bar)
   at __Substitutions.System.Threading.Monitor.TryEnterRaw(Object lock, Int32 timeOut, MSyncVarOp operation, String name)
   at __Substitutions.System.Threading.Monitor.Enter(Object lock)
   at Bank.Account.Withdraw(Int32 amount)
   at TestBank.ChessTest.<Run>b__0(Object o)
   at Microsoft.ManagedChess.EREngine.Helper.<>c__DisplayClass18.<WrapParamThreadStart>b__17(Object o)
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart(Object obj)

user breakpoint requested:
   at Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break(String message)
   at Microsoft.ExtendedReflection.Utilities.Safe.Diagnostics.SafeDebugger.Break()
   at Microsoft.ManagedChess.EREngine.ClrSyncManager.DebugBreak()
   at Microsoft.ManagedChess.ShimSyncManager.DebugBreak(ShimSyncManager* )
   at Chess.LocalBacktrack()
   at Microsoft.ManagedChess.MChessChess.LocalBacktrack()
   at Microsoft.ManagedChess.EREngine.Helper.<>c__DisplayClassa.<WrapAcquire>b__8(ClrSyncManager manager)
   at Microsoft.ManagedChess.EREngine.Helper.SimpleWrap[T](SimpleDelmanager`1 foo, SimpleDel`1 bar)
   at Microsoft.ManagedChess.EREngine.Helper.WrapAcquire(BlockingAcquire b, NonBlockingAcquire nb, Object o, MSyncVarOp mop, String instrMethod)
   at __Substitutions.System.Threading.Thread.Join(Thread thread)
   at TestBank.ChessTest.Run()
   at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.ManagedChess.EREngine.ChessMain..ctor(MChessOptions m, Assembly a, String tc)
   at Microsoft.ManagedChess.Base.Program.Execute()
   at Microsoft.ManagedChess.Base.Program.Main(String[] args)

ChessTest.Run returned false.

Chess finds an issue with my usage of Threading.Interlocked, but I can't figure out how I'm incorrect.

Wed, 01 Jul 2009 11:01:14 Z

So I have a linked list implementation which allows multiple producers but just one consumer, and doesn't use CAS. I wanted to test if it was incorrect, so I downloaded Chess and tried it out. The test failed, and I used the reproducing facilities to figure out where it is failing. But, from what I can tell, this failure is impossible. It's like Interlocked.Exchange is not behaving atomically or isn't placing memory barriers.

Here is what I am testing:

        [System.Diagnostics.DebuggerDisplay ("{id}")]
        private class Node {
            public Node next;
            public readonly int id;
            public Node(int id)
            {
                this.id = id;
            }
        }
        private class LinkedList {
            public readonly Node head;
            private Node insertionPoint;
            public LinkedList()
            {
                head = insertionPoint = new Node(0);
            }
            public void Insert(int id)
            {
                Node newNode = new Node(id);
                //notice that the value exchanged for insertionPoint is *always new*
                //therefore, after this next line finishes, oldInsertionPoint != insertionPoint
                Node oldInsertionPoint = Interlocked.Exchange(ref insertionPoint, newNode);
                //we may be preempted here; but the new nodes will just go after us
                //so they'll be implicitely added when we finish
                oldInsertionPoint.next = newNode;
            }
        }
        [TestMethod()]
        [HostType("Chess")]
        public void Test()
        {
            //prep
            var list = new LinkedList();
            var t = new Thread(() => { list.Insert(-1); });

            //run
            t.Start();
            list.Insert(1);
            list.Insert(2);

            //finish
            t.Join();
            int count = 0;
            for (Node n = list.head; n.next != null; n = n.next) count += 1;
            Assert.AreEqual(count, 3);
        }

Here is what Chess produces for reproduction:

[TestProperty("ChessMode","Repro")]
[TestProperty("ChessBreak","BeforePreemption,AfterPreemption")]  
#region ChessScheduleString (not human readable)
[TestProperty("ChessScheduleString",@"bpilaiaaaaaaaaaaaeaaonlnahgabmejjgcfcgcpgnmkhlhpekpfeknhoahekbaiiagabdcenijaeabaommbiimnogjcombngjeh
cdcjklckibmkgffggffnggbgeammonjnlmphnohloplnphnohloplnphlkdljneochphnpppdpfmgggeabgmpgmoeknkmjjocbia
kkmibpdphohmbpdpcchomnfpodnhpidfpappfpfhhpponplpkgpmdelpppbgpkplkpoflfmbopdpkgdppbppfpephpocllfpedhp
pkopjkppjlohpppohpaaldcaoojfhfaaaaaa")]
#endregion

Alright. So let's explore what is happening. The testing thread gets into Insert(1), and preempts on the Interlocked.Exchange line. The worker thread starts, exchanges node -1 for node 0, and finishes. The testing thread comes back, and the problems start. After the Exchange line has finished, both oldInsertionPoint and insertionPoint are set to node -1, but we provided node 1 to the exchange call so we should have exchanged node 1 for node -1, and new insertionPoint should now be node 1.

Am I mistaken in how I believe Interlocked.Exchange works, or is this some other issue?

Chess - Visual Studio Support

Thu, 25 Jun 2009 06:33:45 Z

Hi, Does Chess support only Visual Studio 2008 version, or does it work with previous versions as well? I've VS2005 on my PC. MY application is a single thread graphical application written in c++, which i've parellelized to an extent. Can i use Chess in some way to find the concurrency issues with my application?

CHESS for non-Windows platforms

Fri, 03 Jul 2009 08:21:01 Z

Hi,

i discovered CHESS recently and it seems to me really interesting.
I'm currently working on mobile phone platform and we are integrating complex software onto a SMP platform. Unfortunately the OS used is not Windows. Do you know if anybody already tried to port CHESS on other OSes?

Thanks in advance.

Feedback on the new version of Chess

Wed, 17 Jun 2009 08:58:50 Z

Hi,

I've been collating some notes on the new version of Chess, so here it goes:

Chessboard:

Chessboard very useful - I especially like the cumulative parameters support. On the whole it makes mchess much more usable.
Chessboard uses up nearly 50% CPU when idle
Chessboard refreshes the stdout and stderr at a regular interval when running a test. However, it would be nice if it refreshed once again, after the test is complete so that it flushes the remaining data into the UI. Not a big deal, since I can just hit the refresh button.
It doesn't look like Chessboard supports the /continue option.

Once in a while I get this exception from Chessboard:

System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
   at System.ThrowHelper.ThrowKeyNotFoundException()
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at ChessBoard.TaskList.model_SelectionUpdateEvt(State t, State s)
   at ChessBoard.Handler`2.Invoke(T t, S s)
   at ChessBoard.Model.SelectionUpdateNotify(State previous, State current)
   at ChessBoard.Selection.Update(Object sender, XElement xelement, Boolean doubleclick)
   at ChessBoard.Explorer.Explorer_Enter(Object sender, EventArgs e)
   at System.Windows.Forms.Control.OnEnter(EventArgs e)
   at System.Windows.Forms.Control.NotifyEnter()
   at System.Windows.Forms.ContainerControl.UpdateFocusedControl()

Selecting "Repeat test->With Bounds->5 seconds" gives the message "Unrecognized argument /timeout:5".
Strictly nice-to-have : MRU list of testlists

mchess:

Does the /logging argument do more than just printing the .NET framework version?
The /showprogress argument doesn't really print anything to indicate how many schedules are remaining. Maybe this only works for really long-running tests?
The /di argument is very very useful! Can it also print the thread-ids/names that are included in the profiling? Also, when it prints out the list of types, can it be sorted? In some of my tests this list tends to be pretty big.
I've also seen mchess trigger the assertion in vector, that someone's already posted about
In a future release can you also add support for Thread.Abort() ? It claims that it's not a good practice to use it but nevertheless it's in our code so would be nice to have it supported.
Regarding Livelocks - repro+trace goes into an infinite loop (naturally, since its a livelock). It would be nice if mchess can detect and support viewing the trace in Concurrency Explorer. For bonus points it could also print the repeating stack trace (although I can figure this out by looking at the trace file)
This may or may not be possible - I have some tests that require long-running background threads and singleton objects that don't sit well with multiple iterations of the Run() method. It would be nice to have an option to run each iteration in a new AppDomain.

Misc:

In the Chessworkflow.doc document the example specifies /ia:d1.dll whereas it should be /ia:d1
ConcurrencyExplorer - I think I read somewhere that the "colorbox" style was used only internally during chess development. If you're planning to get rid of it in future versions, please keep it! I often find it useful, especially since it syncs with the source-code view.

Overall, I've found the new version a big improvement, so thanks for your hard work!

--Amit

CHESS should handle config files correctly.

Mon, 15 Jun 2009 18:27:29 Z

I'm disappointed that the effort wasn't done on fixing the loading of config files correctly. This in my mind is the most important bug that makes the whole app useless.

concurrency explorer

Wed, 24 Jun 2009 18:10:27 Z

A.
Chess found a possibility of datarace and a deadlock in code:
1. Found data race at add_Changed:NONE(0)
2. Deadlock

I am not interested in the datarace for now and want to concentrate on the deadlock. So when I right click and try to reproduce with trace, it just runs to 1. and does not reproduce the deadlock - which I want to view in concurrency explorer. Guess this might be related to another minor issue I reported for chessboard/concurrency explorer.

B.
Along with the concurrency explorer, in case a test fails with deadlock, would it be possible to present a simple matrix showing:
XAxis: Threads (with whatever identifier)
YAxis: Resources involved

In the cell itself, you mark, is the thread waiting on the resource (W) or locked on the resource (L). I guess we are not interested in threads not involved, maybe they can be hidden from this view by default.

Double clicking on a cells could open up whatever representation of callstack the tool maintains for that thread at the point of time of deadlock.

I can get all this info by breaking into the debugger and watching the threads/callstacks, but an easy to see diagram may be helpful if it could be generated in the chess tool itself. It is easy to show others the issue too :)

Minor Release v0.1.30626.0, 06/26/2009

Thu, 02 Jul 2009 23:42:50 Z

v0.1.30626.0, 06/26/2009

Available at http://research.microsoft.com/en-us/projects/chess/download.aspx

· Added

1. Support for config files (CHESS creates a separate AppDomain to run the CHESS test in when a config file is present)

2. /maxexecsteps:N option to mchess

3. /dontpreemptmethod:M option

4. Dekker example to Samples

5. SDK material (headers)

· Fixed

1. Problem with Interlocked.Exchange

2. Multiple executions in a trace bug

3. 'Race' on script-initiated window-closing in ChessBoard

4. BankAccount testlist.xml file

· Misc.

1. Optimized /dontpreemptX implementation

2. Sort the output of /diagnose

CHESS and COM

Mon, 29 Jun 2009 15:13:23 Z

Hi,

Does chess work with MTA COM components?

Chessboard crashes

Sun, 28 Jun 2009 11:08:29 Z

Hi,
i was just roaming through the docs and found Chessboard. I tried to start it as recommended but it crashes immediately. I use Windows Vista Ultimate 32bit with an admin account. What follows is a copy and paste from the console window:

Setting environment for using Microsoft Visual Studio 2008 x86 tools.

c:\Program Files\Microsoft Visual Studio 9.0\VC>cd \

c:\>cd I:\Developer\VS2008\Projects\Demos\Microsoft Research\ChessSamples\Sample
s\Managed\BankAccount

c:\>chessboard.exe

Unbehandelte Ausnahme: System.UnauthorizedAccessException: Der Zugriff auf den P
fad "c:\session.xml" wurde verweigert.
   bei System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   bei System.IO.FileStream.Init(String path, FileMode mode, FileAccess access,
Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions
options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy)
   bei System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access,
FileShare share)
   bei System.Xml.XmlWriter.Create(String outputFileName, XmlWriterSettings sett
ings)
   bei System.Xml.Linq.XDocument.Save(String fileName, SaveOptions options)
   bei System.Xml.Linq.XDocument.Save(String fileName)
   bei ChessBoard.Session..ctor(Model model, FileInfo sessionfile)
   bei ChessBoard.Model.StartSession(FileInfo sessionfile, IEnumerable`1 batchco
mmands)
   bei ChessBoard.Program.Main(String[] args)

c:\>

Greetings, Cyron

Can a get more information than "Test Failed"

Thu, 25 Jun 2009 18:18:59 Z

Hi,

Just moved to the latest version of Chess, and now instead of getting a description of the unit test failure I just get "Test Failed".

I tried it on this very simple test:

        ///<summary>
        /// A test for Start
        ///</summary>
        [TestMethod()]
        [Timeout(10000)]
        [HostType("Chess")]
        public void ExecuteStandardTest()
        {
            Assert.AreEqual(true, false);
        }

How can I get a little more information than this?

Without using Chess I get: "Assert.AreEqual failed. Expected:<True>. Actual:<False>." and a stack trace.

Obviously in this simple example it not much of a problem. But my real unit test are much more complex.

Thanks

Andy

Debug assertion failed - mchess

Tue, 16 Jun 2009 23:09:22 Z

CHESS found a deadlock in some code I am looking at.

So I checked that there is some part of the code where an object which is being locked is locked again within this code (basically a bug), but when I make some changes in the code for this (basically not a fix, I just commented the inner lock on the same object out), Mchess gives this assert when run the test:

----
Microsoft Visual C++ Debug Library

Debug Assertion Failed!

Program: ...ram File\Microsoft Chess\bin\Microsot.ManagedChess.Base.exe
File: C:\Program Files\Microsoft Visual Studio 9.0\VC\include\vector
Line: 764

Expression: vector subscript out of range
etc.
----

This error itself is not deterministic though - sometimes it runs and find the new deadlock, sometimes it shows this error.

(Is there an image attach on the forum? Thanks)

Sriram

Instrumenting code running in a separate AppDomain

Thu, 18 Jun 2009 16:28:09 Z

Hi,
Does Chess recognize and instrument code that is dynamically loaded and run in a separate AppDomain ? In other words, if I create a new AppDomain in the Run() method, execute a method in the new domain that creates threads, will Chess instrument these threads?

Thanks,
-Amit