ASP.NET 2.0 Crash case study: Unhandled exceptions

For a long time all my case studies have been on 1.1. it’s time to venture out in 2.0 land and look at what may seem like a 2.0 specific issue.

I say “may seem” because this case study will only directly crash if you are using 2.0, but as you’ll learn later the problem existed in 1.1 and 1.0, it was just way harder to track down.

Problem description:

Once in a while ASP.NET crashes and we see events in the system event log like this one

Event Type: Warning
Event Source: W3SVC
Event Category: None
Event ID: 1009
Date: 2006-04-25
Time: 09:41:22
PM User: N/A
Computer: SUBSPACE1
Description:
A process serving application pool 'ASP.NET V2.0' terminated unexpectedly. The process id was ‘1732’. The process exit code was ‘0xe0434f4d’.

Or this one

Event Type: Warning

Event Source: W3SVC

Event Category: None

Event ID: 1011

Date: 2006-04-25

Time: 09:41:22

User: N/A

Computer: SUBSPACE1

Description:

A process serving application pool 'ASP.NET V2.0' suffered a fatal communication error with the World Wide Web Publishing Service. The process id was '6256'. The data field contains the error number.

And in the application event log we get a pretty cryptic error message like this one

Event Type: Error

Event Source: .NET Runtime 2.0 Error Reporting

Event Category: None

Event ID: 5000

Date: 2006-04-25

Time: 09:41:20

User: N/A

Computer: SUBSPACE1

Description:

EventType clr20r3, P1 w3wp.exe, P2 6.0.3790.1830, P3 42435be1, P4 app_code.pn5mfdcr, P5 0.0.0.0, P6 444dcf44, P7 5, P8 5, P9 system.dividebyzeroexception, P10 NIL.

Initial thoughts:

Ok, so what do we know about the issue? We know that asp.net terminated unexpectedly, and that right before this we got a System.DivideByZeroException…. We also know that the process exit code was 0xe0434f4d whatever that means, hmm…

Usually when you get a stopped unexpectedly error message the exit code will be the type of exception that caused the crash. For example a 0xC0000005 means you got a second chance access violation, 0x800703e9 means you suffered a StackOverflowException but what about 0xe0434f4d?

0xe0434f4d is the exception code for CLR (.net) exceptions, so any managed exception like a NullReferenceException or InvalidOperationException or SQLException… basically all managed exception are natively referred to as 0xe0434f4d. In this case, if we look closer at the application event log entry we can see that it is in fact a System.DivideByZero exception.

Trivia: Justa piece of info of no particular value that you might want to pull out of pocket on your next dateJ 0xe0434f4d or at least 43 4f 4d are the ASCII values for the letters COM.

But hey now… should a .net exception cause the asp.net process to crash??? If you divide by zero in your page and don’t have a try catch block around it, surely you will get one of those “nice” white and yellow error pages saying that an exception occurred on your page, but the process doesn’t just exit.

The answer is yes, you will get one of those pages because the asp.net global error handler will eventually catch your exception, format it for you and print it out on the screen. But what happens if it is not on an asp.net request, so there is no-one to feedback the exception to? It’s the old paradox: If a tree falls in the forest and nobody is there, does it still make a sound?

In 1.0 and 1.1 it didn’t. For example if you throw an exception in a piece of code called on a timer, or use QueueUserWorkItem and throw an exception in code executing there, or otherwise throw exceptions in code that is not running inside the context of an asp.net request, the framework will swallow the exception and continue. Or rather it will stop that thread of execution but it won’t die.

Doesn’t sound all that bad right? Really???

That thread could have been doing anything, and we will never be the wiser that it died. It could have been holding a lock of some sort, or it could have been in the middle of cleaning up resources, or really a number of different things that will now never happen, but that may immediately or eventually have really bad side effects like hangs or crashes or memory issues, but the exception will be long gone so we cant figure out what it was.

The policy for unhandled exceptions was changed in ASP.NET 2.0 to the default for .net which is a process exit. This can be changed back by adding the following to the aspnet.config in the frameworks directory, but I wouldn’t recommend it without putting in some preventive measures to take care of potential unhandled exceptions on non ASP.NET threads.

<configuration>

<runtime>

<legacyUnhandledExceptionPolicy enabled="true" />

</runtime>

</configuration>

Troubleshooting the issue:

The main task here is to find out where this DivideByZero exception is coming from and why it occurred so there are two ways to figure this out (short of complete code inspection).

Strategy #1 – logging the exception

The first way, and this is the way I would probably recommend, is to create an UnhandledExceptionHandler to log the exception along with its stack trace in the event log as shown in this article https://support.microsoft.com/?id=911816

You add the handler like this to the web.config:

    <system.web>

      <httpModules>

        <add type="WebMonitor.UnhandledExceptionModule, <strong name>" name="UnhandledExceptionModule"/>

      </httpModules>

…

    </system.web>

And it hooks an eventhandler up to the UnhandledException event of the current app domain.

You don’t actually need to strong name it and add it to the GAC, however if you plan it in multiple applications you should to avoid for the dll being loaded multiple times.

Now the next time you get one of these unhandled exceptions, the process will still exit (unless you change the unhandled exception policy), but you have a very good chance of fixing the issue.

The event for the exception in this particular sample looks like this…

Event Type: Error

Event Source: ASP.NET 2.0.50727.0

Event Category: None

Event ID: 0

Date: 2006-04-25

Time: 09:41:20

User: N/A

Computer: SUBSPACE1

Description:

UnhandledException logged by UnhandledExceptionModule.dll:

appId=/LM/w3svc/1/ROOT/CrashMe

type=System.DivideByZeroException

message=Attempted to divide by zero.

stack=

   at MyFinalizerClass.Finalize()

.

Bingo!!! So the exception occurs in MyFinalizerClass.Finalize() in the CrashMe application.

In fact the code for the finalizer for this class looks like this, so it is pretty obvious what caused it, and our work here is done…

    ~MyFinalizerClass()

    {

        int i = 0;

        int j = 9;

        i = j / i;

    }

Setting up an UnhandledException handler like this is not limited to 2.0. You can absolutely do this in 1.1 as well to determine if you are throwing any unhandl

• Anonymous
  April 27, 2006
  Thank you for taking the time to write these articles.  Before reading your side, I'd never really comprehended windbg.  Your articles helped me use windbg to diagnose and solve some managed memory leaks in my code.  In previous positions, I'd used Rational Purify to find them, but windbg seems better to me for finding leaks.

• Anonymous
  April 27, 2006
  Your blog rocks! It's indeed much better than many debugging books out there. I really like the way you present the problem and how you approach it mostly with the help of windbg. Reading your blogs has given me very good perspectives on what's under the covers.
  
  Please keep those coming.

• Anonymous
  April 27, 2006
  PingBack from http://www.epocalipse.com/blog/2006/04/27/aspnet-20-unhandled-exceptions-and-lucenenet/

• Anonymous
  April 27, 2006
  Have you ever experienced the 0xe0434f4d exit code and thought, what the heck is that!
  Tess has a nice...

• Anonymous
  April 28, 2006
  Tess, your blog is great. It has helped me out a lot, especially this post. Keep it going!

• Anonymous
  April 29, 2006
  This is very cool.  Thanks for your hard work putting this together!

• Anonymous
  May 01, 2006
  This is a basic article but never the less it seems that many ASP.NET programmer don't know issue like this.
  
  Tess I really think that you are doing a great job in advancing the debugging operation made by ASP.NET developers.
  
  ASP.NET developer have to understand that they must understand the concept of debugging because sooner or later they will come into the situation that they will face a problem that have to be debugged.
  
  Thank you and keep the good job :)

• Anonymous
  May 02, 2006
  I came across this post about dealing with unhandled ASP .NET exceptions on the blog of one of the Microsoft...

• Anonymous
  May 04, 2006
  TCPView
  
  TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints...

• Anonymous
  May 04, 2006
  Awsome!!!!!!!!!!!!
  
  Your's indeed is the best blog on debugging I have ever come across. Please keep them coming :o)
  

• Anonymous
  May 07, 2006
  unintelligible

• Anonymous
  May 10, 2006
  Рекомендую почитать блог &amp;laquo;If broken it is, fix it you should&amp;raquo;. Детально рассматриваются различные...

• Anonymous
  May 10, 2006
  There is a better UnhandledExceptionHandler here: http://dotnettricks.com/blogs/andrewcainblog/archive/2006/04/18/ELMAH_for_ASPNET2_0.aspx

• Anonymous
  May 12, 2006
  Tłumaczenie rewelacyjnego tekstu Tess Ferrandez o radzeniu sobie z wyjątkami, kt&#243;re nie sa tak do końca oczywiste i co najgorsze są przed nami ukryte.

• Anonymous
  May 16, 2006
  The following links to .NET resources have been collated over time with the assistance of
  
  colleagues.&amp;nbsp;...

• Anonymous
  May 21, 2006
  Tess really has the best blog I've seen that discusss how to investigate runtime issues with ASP.NET.&amp;nbsp;...

• Anonymous
  June 06, 2006
  Trackback from dotnetkicks.com

• Anonymous
  June 14, 2006
  I came across a great article that discusses how to investigate runtime issues with ASP.NET.&amp;nbsp; Tess&amp;nbsp;is...

• Anonymous
  July 06, 2006
  TCPView
  
  TCPView is a Windows program that will show you detailed listings of all TCP and UDP endpoints...

• Anonymous
  July 17, 2006
  Hi Tess, I've got a dump from an ASP.NET app that is not crashing, but it becomes extremely slow for apparently no reason. The # of connections to IIS grows, and the users get no response from the server, although CPU and memory comsumption are low, and things only get back to normal with an app pool restart. I've got the dump with IIS Debug&Diag Tools, and the report shows for several (24) threads that "this thread is blocked by an unhandled exception". !threads shows that of the 36 threads listed, 24 have Lock Count = 1 and Exception = "(Threadpool Worker) System.ArgumentException". I've located the exception for one of those threads with !dso and !do to use what you've shown in the post, but _remoteStackTraceString is 0x00000000. What does that mean? And how can a thread be blocked by an unhandled exception? The app is .NET 1.1 SP1. Shouldn't the framework "swallow" the exception as you said? One more thing that could be related: the app is sending e-mail messages to warn some people about unhandled exceptions, via the global ASP.NET exception handler, and this handler has been quite busy with the ThreadAbortExceptions generated by Response.Redirect. Thanks for any help on this....

• Anonymous
  July 17, 2006
  Hi GB,
  
  Perhaps you can show the stack of one of the blocked threads, that would help determining why it is blocked (both !clrstack and kb, but you can mark out any proprietary information if you want with some suitable marker like ##### or something).  
  
  Member variables of exceptions (such as remotestacktracestring) are not always filled in, particularly the remote stack trace is not relevant to an ArgumentException, it is just an inherited member.  There should be a _StackTraceString, but if you are in the middle of the exception it might not be filled out yet. If that is the case you can get the stack directly by doing !clrstack or !dumpstack
  
  

• Anonymous
  July 18, 2006
  The comment has been removed

• Anonymous
  July 21, 2006
  The comment has been removed

• Anonymous
  July 24, 2006
  Ok Tess,
  
  Thanks a lot. That's was my conclusion too, I'm writing it now on my report. Perhaps I could quote you on this?.....
  
  ;) just kidding
  
  Thanks,
  
  GB

• Anonymous
  July 26, 2006
  Feel free:)

• Anonymous
  August 10, 2006
  This helped us with part of our problem, but IIS keeps crashing over exception 0x00015dea.  I have been trying to figure out what this exception refers to, but I can't find it.

• Anonymous
  August 10, 2006
  Hi TM,
  
  To be honest that looks more like an address than an exit code or an exception code.  In fact that address often shows up as the faulting address in kernel32 during a fatal exception.
  
  I would run adplus straight up in crash mode (without any config files to begin with) and look at the dump that gets generated when the process exits, as well as the log files to look for strange exceptions before the exit.  
  
  HTH

• Anonymous
  September 05, 2006
  The comment has been removed

• Anonymous
  September 06, 2006
  Hi Mash,
  
  The exception address is only available in sos.dll for 2.0, and just in case you are debugging for the unhandled exception, that only happens in 2.0.
  
  But... if you are interested in that format exception you should be able to find it using !dumpheap -type FormatException
  
  

• Anonymous
  September 18, 2006
  I'm getting the same error too. I'm also getting Thread aborts and a crashing IIS. I think the source is the .Redirect, because my application is logging this it's own log in a database.
  
  Anyone found a solution for this?

• Anonymous
  September 18, 2006
  The comment has been removed

• Anonymous
  September 19, 2006
  Uhm, yes, your right. Saw that a couple of minutes ago. I've installed IIS diagnostics (max crash logging) and now it's waiting for the next crash.
  Thanks for the quick reply!

• Anonymous
  November 08, 2006
  As part of my &quot;not-my-real-job&quot; time, I do a little website hosting - basically to keep my

• Anonymous
  November 13, 2006
  This is more a general question about HttpModules, all the documentation seems to suggest that when you add an HttpModule to your web.config file you only get one single instance of your HttpModule per HttpApplication, is this really true? I've been running some load tests generating 1000s of requests and when I've windbg'd the worker process and done a dumpheap -type on my HttpModule class there's loads of 'em. But if we're only supposed to get one instance per HttpApplication, how's this possible?

• Anonymous
  November 14, 2006
  Actually it appears that ASP.NET creates a pool of HttpModules to handle multiple requests and the number created increases with load. I wonder what algorithm is used to determine how many instances of the HttpModule to create? So this would mean that the HttpModule code from the kb article will only work for the first instance of that particular HttpModule. Well, you learn something everyday day.

• Anonymous
  November 14, 2006
  I am afraid I don't follow you at all... What is the problem?  If you get an unhandled exception, this module will handle it whether there is a pool of such handlers or only one.  Are you seeing something different? I would be a bit surprised if you were...

• Anonymous
  November 15, 2006
  What I mean't was that in the kb article the code uses a static bool to determine whether the module has already been initialized and hence to hook up the event handlers or not in the Init() method. So when any subsequent instances of the module class are created this bool flag is already set to true. Which means these instances will not have event handlers set up for them. Well, thats what it seems like anyway, as a % of my requests don't get processed. The first x number do, then it goes hit & miss. This only happens under heavy load, ie when I've got a pool of these handlers created. Everytime I've had a request that hasn't been processed I've checked with !dumpheap -type and there's always multiple instances of the module class. When I comment out the static bool flag all my requests get processed when it's under load. Hope that makes sense.

• Anonymous
  November 30, 2006
  Just in case anyone uses active reports, we ran across an issue where our application was terminating unexpectedly and it turned out to be related to a bug in their code. http://www.datadynamics.com/forums/3/96793/ShowPost.aspx#96793

• Anonymous
  January 20, 2007
  Hi Tess, I cannot use a debugger to troubleshoot the issue in this case. The HttpModule you referred to works for a ASP.NET app. Can you give me some idea on how to do this for a Windows Service (in 2.0) that is doing some async operations for TCP Sockets? Thanks, Warrier

• Anonymous
  January 21, 2007
  Hi Warrier, Unfortunately a windows service is not "hosted" the same way that an asp.net app is so as you mentioned you don't have the same harness of events, modules and handlers, so you would have to create a harness yourself which is not completely trivial (ok, understatement of the year:))   Where do you get the exceptions? Would it be possible to have exception handlers just around the code that makes the async operations?

• Anonymous
  February 22, 2007
  Hi Tess, I'm new to WinDbg and you blog was very helpful! I've got a question...When I run my application, the worker process crashes.. i started debugging using WinDbg.. when I open crash dumps, following exceptions is shown In w3wp__PID__1368__Date__02_22_2007__Time_11_07_03AM__329__Second_Chance_Exception_E0434F4D.dmp the assembly instruction at kernel32!RaiseException+53 in C:WINDOWSsystem32kernel32.dll from Microsoft Corporation has caused a CLR Exception of type (System.CannotUnloadAppDomainException) on thread 14 This exception originated from mscorwks!RaiseTheExceptionInternalOnly+226. Thread 14 - System ID 1568 Entry point   mscorwks!ThreadpoolMgr::intermediateThreadProc Create time   2/22/2007 10:56:57 AM Time spent in user mode   0 Days 0:0:16.625 Time spent in kernel mode   0 Days 0:0:25.46 Function     Arg 1     Arg 2     Arg 3   Source kernel32!RaiseException+53     e0434f4d     00000001     00000001     mscorwks!RaiseTheExceptionInternalOnly+226     1d00e1d0     00000000     00000000     mscorwks!RaiseTheException+4c     1d00e1d0     00000000     019dfb68     mscorwks!RaiseTheException+be     00000000     000e1f00     b59aaf96     mscorwks!RealCOMPlusThrow+37     1d00e1d0     00000000     7a0e0701     mscorwks!RealCOMPlusThrow+a     1d00e1d0     b40c20e3     7a36a7d0     mscorwks!Thread::RaiseCrossContextException+63     00000000     019dfc18     019dfc88     mscorwks!Thread::DoADCallBack+26c     00000007     79f3a0a1     019dfd88     mscorwks!Thread::UserResumeThread+e1     019dfd88     019dfd34     79f93fe6     mscorwks!Thread::DoADCallBack+355     019dfd88     b40c26eb     00000001     mscorwks!Thread::DoADCallBack+541     019dfd88     00000007     00000000     mscorwks!Thread::DoADCallBack+575     00000007     7a07bd61     019dfdf8     mscorwks!ManagedThreadBase::ThreadPool+13     00000007     7a07bd61     019dfdf8     mscorwks!QueueUserWorkItemCallback+9d     00110a90     77e6bb9d     7a38e228     mscorwks!ThreadpoolMgr::ExecuteWorkRequest+40     08e67868     b40c2503     00000000     mscorwks!ThreadpoolMgr::WorkerThreadStart+1f2     00000000     00000000     00000000     mscorwks!ThreadpoolMgr::intermediateThreadProc+49     000c89a0     00000000     00000000     kernel32!BaseThreadStart+34     79f710dd     000c89a0     00000000     Using this information i am not able to figure out where the error is occured. Also I am creating timer on thread in ASP.Net application and the timer is disposed in Application_End event. Can you give me some idea where should i start looking inorder to resolve the issue? Thanks manche

• Anonymous
  February 22, 2007
  You can try to run !threads to see what the last exception was on that thread and run !pe on it,  or run !dso to find the exception on the stack.  It is definitely an unhandled .net exception but it is not possible from the stack you sent to see what the exception was.

• Anonymous
  February 23, 2007
  Thanks for your response... 0:014> !threads PDB symbol for mscorwks.dll not loaded ThreadCount: 10 UnstartedThread: 0 BackgroundThread: 10 PendingThread: 0 DeadThread: 0 Hosted Runtime: no                                      PreEmptive   GC Alloc           Lock       ID OSID ThreadOBJ    State     GC       Context       Domain   Count APT Exception  14    1  620 000e1f00   1808220 Enabled  00000000:00000000 000dee68     0 STA (Threadpool Worker) System.CannotUnloadAppDomainException (1d00e1d0)  16    2  630 000ee228      b220 Enabled  00000000:00000000 000dee68     0 MTA (Finalizer)  17    3  880 00101f60    80a220 Enabled  00000000:00000000 000dee68     0 MTA (Threadpool Completion Port)  18    4  884 00105340      1220 Enabled  00000000:00000000 000dee68     0 Ukn  12    5  1ec 05983130   880a220 Enabled  00000000:00000000 000dee68     0 MTA (Threadpool Completion Port)  20    6  7c4 00176e68   180b220 Enabled  00000000:00000000 000dee68     0 MTA (Threadpool Worker)  21    7  9c0 059def98   880b220 Enabled  00000000:00000000 000dee68     0 MTA (Threadpool Completion Port)  25    a  e6c 08cf8f58   180b220 Enabled  00000000:00000000 109aedd0     1 MTA (Threadpool Worker)  26    b  78c 08d80370   880b220 Enabled  00000000:00000000 000dee68     0 MTA (Threadpool Completion Port)  28    c  f38 108e8770      7221 Enabled  00000000:00000000 1090fd38     0 STA 0:014> !dso OS Thread Id: 0x620 (14) ESP/REG  Object   Name 019df9f8 1d00e1d0 System.CannotUnloadAppDomainException 019df9fc 1d00e1d0 System.CannotUnloadAppDomainException 019dfa44 1d00e1d0 System.CannotUnloadAppDomainException 019dfa58 1d00e1d0 System.CannotUnloadAppDomainException 019dfaac 1d00e1d0 System.CannotUnloadAppDomainException 019dfab8 1d00e1d0 System.CannotUnloadAppDomainException 019dfb54 1cfe9cb4 System.CannotUnloadAppDomainException 019dfb58 1d00cc54 System.Byte[] 019dfb84 1d00e1d0 System.CannotUnloadAppDomainException 019dfb88 1d00cc54 System.Byte[] 019dfb98 1d00cc54 System.Byte[] 019dfc24 022e5f28 System.Threading.ExecutionContext 0:014> !pe Exception object: 1d00e1d0 Exception type: System.CannotUnloadAppDomainException Message: Error while unloading appdomain. (Exception from HRESULT: 0x80131015) InnerException: <none> StackTrace (generated): <none> StackTraceString: <none> HResult: 80131015 0:014> !do 1d00e1d0 Name: System.CannotUnloadAppDomainException MethodTable: 7915d434 EEClass: 791e7ea4 Size: 72(0x48) bytes (C:WINDOWSassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 790fa3e0  40000b5        4        System.String  0 instance 1d00f048 _className 79109208  40000b6        8 ...ection.MethodBase  0 instance 00000000 _exceptionMethod 790fa3e0  40000b7        c        System.String  0 instance 1d00f7d8 _exceptionMethodString 790fa3e0  40000b8       10        System.String  0 instance 1d00f194 _message 79113dfc  40000b9       14 ...tions.IDictionary  0 instance 1d0104fc _data 790fa9e8  40000ba       18     System.Exception  0 instance 00000000 _innerException 790fa3e0  40000bb       1c        System.String  0 instance 00000000 _helpURL 790f9c18  40000bc       20        System.Object  0 instance 00000000 _stackTrace 790fa3e0  40000bd       24        System.String  0 instance 00000000 _stackTraceString 790fa3e0  40000be       28        System.String  0 instance 1d011274 _remoteStackTraceString 790fed1c  40000bf       34         System.Int32  0 instance        0 _remoteStackIndex 790f9c18  40000c0       2c        System.Object  0 instance 00000000 _dynamicMethods 790fed1c  40000c1       38         System.Int32  0 instance -2146234347 _HResult 790fa3e0  40000c2       30        System.String  0 instance 1d00fa2c _source 790fe160  40000c3       3c        System.IntPtr  0 instance        0 _xptrs 790fed1c  40000c4       40         System.Int32  0 instance        0 _xcode 0:014> !do 1d00f048 Name: System.String MethodTable: 790fa3e0 EEClass: 790fa340 Size: 92(0x5c) bytes (C:WINDOWSassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) String: System.CannotUnloadAppDomainException Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 790fed1c  4000096        4         System.Int32  0 instance       38 m_arrayLength 790fed1c  4000097        8         System.Int32  0 instance       37 m_stringLength 790fbefc  4000098        c          System.Char  0 instance       53 m_firstChar 790fa3e0  4000099       10        System.String  0   shared   static Empty    >> Domain:Value  000dee68:790d6584 109aedd0:790d6584 05a4bf60:790d6584 08da9588:790d6584 08e39ef0:790d6584 108cb728:790d6584 1090fd38:790d6584 << 79124670  400009a       14        System.Char[]  0   shared   static WhitespaceChars    >> Domain:Value  000dee68:022d13b8 109aedd0:02ae15b0 05a4bf60:023d4778 08da9588:024d163c 08e39ef0:025a5a2c 108cb728:0268db34 1090fd38:026ea248 <<

• Anonymous
  February 23, 2007
  Opps I accidently clicked on submit button.. I have verified the code and all the threads are disposed. Can you find any details with the give information? Once again thanks for all your help... Thanks manche

• Anonymous
  February 25, 2007
  The comment has been removed

• Anonymous
  February 26, 2007
  The comment has been removed

• Anonymous
  April 26, 2007
  Unhandled exceptions cause ASP.NET-based applications to unexpectedly quit in the .NET Framework 2.0

• Anonymous
  June 02, 2007
  The comment has been removed

• Anonymous
  June 24, 2007
  These are the articles (in no particular order) that I felt best showed a thorough use of the windbg

• Anonymous
  August 09, 2007
  I cannot use a debugger to troubleshoot the issue in this case. The HttpModule you referred to works for a ASP.NET app.

• Anonymous
  October 09, 2007
  Hi Tess, Was hoping if you can give us some direction to look towards based on this  output we got from windbg. This dump file has an exception of interest stored in it. The stored exception information can be accessed via .ecxr. (ec.117c): CLR exception - code e0434f4d (first/second chance not available) eax=1bd7f64c ebx=1b1352d8 ecx=00000000 edx=00000024 esi=1bd7f6d8 edi=e0434f4d eip=77e4bee7 esp=1bd7f648 ebp=1bd7f69c iopl=0         nv up ei pl nz na po nc cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00000202 kernel32!RaiseException+0x53: 77e4bee7 5e              pop     esi 0:033> !anlyze -v No export anlyze found 0:033> !analyze -v

•                                                                             *
•                        Exception Analysis                                   *
•                                                                             *

Thanks, Neil

• Anonymous
  October 09, 2007
  I would start of with !clrstack on the current thread (the one that throws the exception) and ~* e !clrstack to see what all threads are doing to get an idea of why its timing out.

• Anonymous
  October 17, 2007
  The comment has been removed

• Anonymous
  October 17, 2007
  Hi Ben, Sounds like it is not matching up the right version/key in the GAC.  Is that the exact message you get (i.e. "codebase cannot be found")?   You might want to read through this regarding how the probing is done as it might help you figure out why it fails. http://en.csharp-online.net/.NET_CLR_Components%E2%80%94Resolving_Names_to_Locations On a separate note, although it is best practice to store it in the GAC and i wouldn't recommend creating copies in the bin directory for all dlls, this dll is extremely small so removing the strong name and storing this one in the GAC wont really cause any noticeable memory changes, assuming that you dont have hundreds of different applications.

• Anonymous
  October 17, 2007
  Thanks Tess - you're right, the "codebase cannot be found" message is the one I see. How could I add this to the GAC (without a strong name) and reference it in my web.config file, inside the httpModules tag? This entry appears to require a strong name and this is where my error message originates from. Apologies for all the questions - although I've been coding in .NET for a while, I've had little experience in deploying these apps. Thanks again, Ben

• Anonymous
  October 17, 2007
  The comment has been removed

• Anonymous
  October 31, 2007
  This has been a busy month for blogging for me, I'm up to a whopping 8 posts this month including this

• Anonymous
  November 13, 2007
  Hi misters, is it possible use AppDomain.Currentdomain. UnhandledException event en ASP.NET 2.0 ?? I have this code: protected override void OnInit(EventArgs e)        {            base.OnInit(e);            PantallaControlIULogging.TrazarDebug("Principal. OnInit.");            PantallaControlIULogging.TrazarWarning("Principal. CurrentDomain_UnhandledException. ");            AppDomain.CurrentDomain.UnhandledException -= new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);            AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);        } and protected void Page_Load(object sender, EventArgs e)        {            PantallaControlIULogging.TrazarWarning("Principal. CurrentDomain_UnhandledException. ");            AppDomain.CurrentDomain.UnhandledException -= new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);            AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); ... I don't get fire that event when throw an error        protected void b2click(object sender, EventArgs e)        {                // Forzar error                throw new Excepciones.BloqueoTareaExcepcion("ERROR BloqueoTareaExcepcion!!!"); I want to get the error and show it using javascript (alert). By other reasons, I cannot access to global.asax and I cannot use HttpApplication_Error event. Any help will be appreciated, and I'll be very grateful. Thanks in advance. Greetings, regards.

• Anonymous
  November 14, 2007
  Thank you, thank you, thank you, thank you. This helped me solve a major roadblock at work.

• Anonymous
  April 02, 2008
  wow. finally an easy to understand walkthrough on  debugging! What I like is that it's not just the fix but the process of determining what caused the error in the first place and what all the little bits mean. Thank you very much!

• Anonymous
  April 16, 2008
  The comment has been removed

• Anonymous
  April 16, 2008
  It looks right assuming that the strong name is correct, except for that the name should probably be UnhandledExceptionModule rather than UnhandledExceptionMonitor unless you changed the name, in which case it should probably also be changed in the type

• Anonymous
  April 22, 2008
  Hi Tess. hmm was getting tired! Changed that but still doesn't work. I will have another look at it. assuming once I've compiled the dll I can move it between machines, thats not the problem..? Thanks, Matt

• Anonymous
  May 02, 2008
  Thank you, this article was very useful. I had the same issues carrying out the KB instructions on a  production system as Ben Wagenaar mentioned in a previous comment. More about this on: http://andrasvass.blogspot.com/2008/05/aspnet-20-unhandled-exceptions-aka.html I ended up creating installers for the module - you can find them on Codeplex: https://www.codeplex.com/Release/ProjectReleases.aspx?ProjectName=unhandledexception Perhaps it may help Matt solve his deployment problems (if he hasn't already...)

• Anonymous
  May 30, 2008
  Matt, I had the same problem as you. The issue (aside from what Tess mentioned), you're not forming the strong name correctly. You have: type="WebMonitor.UnhandledExceptionModule, Version=0.0.0.0, Culture=neutral, PublicKeyToken=b30ebd417a518934, processorArchitecture=MSIL" What you want is this: type="WebMonitor.UnhandledExceptionModule, UnhandledExceptionModule, Version=0.0.0.0, Culture=neutral, PublicKeyToken=b30ebd417a518934, processorArchitecture=MSIL" Notice the extra "UnhandledExceptionModule, " after the initial class name... Also, Tess, up above (http://blogs.msdn.com/tess/archive/2006/04/27/asp-net-2-0-crash-case-study-unhandled-exceptions.aspx#1081135) Howard brings up a potentially good point. Is he right?

• Anonymous
  December 05, 2008
  I received this error while coding a shared office Add-In. I had put some code in the Finalize-Method. Moving the code to the applications "close" event helped. Lesson learned: Don't mess around with finalize if you dont have to!

• Anonymous
  December 11, 2008
  Just one word to describe my thoughts on this article...Enlightened :)

• Anonymous
  December 28, 2008
  Hi Tess, it's really a good post for debuging crash. The two methods are both practical. Thanks very much for your great tech and expirence.  Thanks for sharing! I'm your fan now :) Keep moving!

• Anonymous
  January 15, 2009
  The comment has been removed

• Anonymous
  January 15, 2009
  could be a lot of things, like running in a different user context etc. I would just get a dump and see what the exception is if you dont get that already from the eventlog entry, and from that try to figure out why it happens. Something is obviously different when you run it in task scheduler vs. manually

• Anonymous
  February 08, 2009
  I know there were already lots of discussions about this topic, but as a .NET developer and support engineer,

• Anonymous
  February 13, 2009
  Thanks! Your article helped me a lot!

• Anonymous
  April 27, 2009
  I know there were already lots of discussions about this topic, but as a .NET developer and support engineer,

• Anonymous
  July 26, 2009
  OK, got the error message on a laptop and I've read all of the above. My question(s) is... What does any of it mean? Can't I just re-install summink to get rid of the error?

• Anonymous
  January 28, 2010
  Hi Tess, Wow what a great article, one of the best I have read, and just what I needed. I have a W3wp web service that has recently started aborting for no apparent reason. Following you excellent tutorials I used WinDbg to try to ascertain the problem. Unfortunately I seem to have hit a brick wall in that when I try to trace back the exception I get stuck in the framework code and am unable to see how to trace back to the root cause. I was was wondering if you could give me any quick hints as to how next to progress in tracing back the real source of this exception. Many thanks for an excellent series. Acby 0:009> !threads ThreadCount: 15 UnstartedThread: 0 BackgroundThread: 13 PendingThread: 0 DeadThread: 1 Hosted Runtime: no                                      PreEmptive   GC Alloc           Lock       ID OSID ThreadOBJ    State     GC       Context       Domain   Count APT Exception   7    1  30c 0169c3f0      8220 Enabled  00000000:00000000 01697520     0 Ukn  16    2 21bc 016aa9d8      b220 Enabled  00000000:00000000 01697520     0 MTA (Finalizer)  18    3  cc8 1a4203a0    80a220 Enabled  00000000:00000000 01697520     0 MTA (Threadpool Completion Port)  19    4 1f5c 1a420cb0      1220 Enabled  00000000:00000000 01697520     0 Ukn  20    5 1484 1a465fc8   180b220 Enabled  407862f8:4078763c 1a421200     0 MTA (Threadpool Worker)  21    6  d38 1a466398   180b220 Enabled  20409550:20409d58 1a421200     0 MTA (Threadpool Worker)  22    7  a54 1a466768   180b220 Enabled  387eaa20:387ec59c 1a421200     0 MTA (Threadpool Worker)  23    8 20fc 1a466b38   180b220 Enabled  20417da0:20417db8 1a421200     0 MTA (Threadpool Worker)   9    9 1270 1a466f08   880a220 Enabled  3cab03ac:3cab15a8 01697520     0 MTA (Threadpool Completion Port) System.InvalidOperationException (3caacbe4) XXXX    a    0 1a4b5d98      9820 Enabled  00000000:00000000 01697520     0 MTA   3    c 1cb4 1a53fe80       220 Enabled  3c920744:3c922704 01697520     0 Ukn  25    b 1064 4a8faac0   200b020 Enabled  387a90fc:387aa520 1a421200     0 MTA  27    d 1f14 1b914a80   200b220 Enabled  20403f98:20405d58 1a421200     1 MTA  28    e 1a84 1b7e00a8    80a220 Enabled  00000000:00000000 01697520     0 MTA (Threadpool Completion Port)  30    f 2324 1a54c8e8   180b220 Enabled  40850890:40850a68 01697520     0 MTA (Threadpool Worker) 0:009> !do 1a466f08 <Note: this object has an invalid CLASS field> Invalid object 0:009> !do 3caacbe4 Name: System.InvalidOperationException MethodTable: 72068c50 EEClass: 71e34b64 Size: 72(0x48) bytes (C:WindowsassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 72080b54  40000b5        4        System.String  0 instance 3caacc3c _className 7207ffc8  40000b6        8 ...ection.MethodBase  0 instance 00000000 _exceptionMethod 72080b54  40000b7        c        System.String  0 instance 3caadacc _exceptionMethodString 72080b54  40000b8       10        System.String  0 instance 3caacd80 _message 7207a4b0  40000b9       14 ...tions.IDictionary  0 instance 3caae330 _data 72080ce8  40000ba       18     System.Exception  0 instance 3caae848 _innerException 72080b54  40000bb       1c        System.String  0 instance 00000000 _helpURL 72080770  40000bc       20        System.Object  0 instance 00000000 _stackTrace 72080b54  40000bd       24        System.String  0 instance 00000000 _stackTraceString 72080b54  40000be       28        System.String  0 instance 3caaf9b0 _remoteStackTraceString 72082da0  40000bf       34         System.Int32  1 instance        0 _remoteStackIndex 72080770  40000c0       2c        System.Object  0 instance 00000000 _dynamicMethods 72082da0  40000c1       38         System.Int32  1 instance -2146233079 _HResult 72080b54  40000c2       30        System.String  0 instance 3caade38 _source 7208341c  40000c3       3c        System.IntPtr  1 instance        0 _xptrs 72082da0  40000c4       40         System.Int32  1 instance        0 _xcode 0:009> !do 3caaf9b0 Name: System.String MethodTable: 72080b54 EEClass: 71e3d65c Size: 2554(0x9fa) bytes (C:WindowsassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) String:    at System.Web.Services.Protocols.WebClientProtocol.ProcessAsyncException(WebClientAsyncResult client, Exception e, String method)   at System.Web.Services.Protocols.WebClientProtocol.ReadResponseAsyncCallback(IAsyncResult asyncResult)   at System.Net.LazyAsyncResult.Complete(IntPtr userToken)   at System.Net.ContextAwareResult.CompleteCallback(Object state)   at System.Threading.ExecutionContext.runTryCode(Object userData)   at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)   at System.Net.ContextAwareResult.Complete(IntPtr userToken)   at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)   at System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 72082da0  4000096        4         System.Int32  1 instance     1269 m_arrayLength 72082da0  4000097        8         System.Int32  1 instance     1268 m_stringLength 72081834  4000098        c          System.Char  1 instance       20 m_firstChar 72080b54  4000099       10        System.String  0   shared   static Empty    >> Domain:Value  01697520:01d801d0 1a421200:01d801d0 << 72081784  400009a       14        System.Char[]  0   shared   static WhitespaceChars    >> Domain:Value  01697520:01d80728 1a421200:01d8548c << 0:009> !do 3caae848 Name: System.NullReferenceException MethodTable: 72070128 EEClass: 71e9e118 Size: 72(0x48) bytes (C:WindowsassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 72080b54  40000b5        4        System.String  0 instance 3caae890 _className 7207ffc8  40000b6        8 ...ection.MethodBase  0 instance 00000000 _exceptionMethod 72080b54  40000b7        c        System.String  0 instance 3caaf630 _exceptionMethodString 72080b54  40000b8       10        System.String  0 instance 3caae91c _message 7207a4b0  40000b9       14 ...tions.IDictionary  0 instance 3caaf938 _data 72080ce8  40000ba       18     System.Exception  0 instance 00000000 _innerException 72080b54  40000bb       1c        System.String  0 instance 00000000 _helpURL 72080770  40000bc       20        System.Object  0 instance 00000000 _stackTrace 72080b54  40000bd       24        System.String  0 instance 00000000 _stackTraceString 72080b54  40000be       28        System.String  0 instance 3caaeb30 _remoteStackTraceString 72082da0  40000bf       34         System.Int32  1 instance        0 _remoteStackIndex 72080770  40000c0       2c        System.Object  0 instance 00000000 _dynamicMethods 72082da0  40000c1       38         System.Int32  1 instance -2147467261 _HResult 72080b54  40000c2       30        System.String  0 instance 3caaf8a4 _source 7208341c  40000c3       3c        System.IntPtr  1 instance        0 _xptrs 72082da0  40000c4       40         System.Int32  1 instance        0 _xcode 0:009> !do 3caaeb30 Name: System.String MethodTable: 72080b54 EEClass: 71e3d65c Size: 2720(0xaa0) bytes (C:WindowsassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) String:    at System.Web.HttpApplication.ThreadContext.Enter(Boolean setImpersonationContext)   at System.Web.HttpApplication.OnThreadEnterPrivate(Boolean setImpersonationContext)   at System.Web.AspNetSynchronizationContext.CallCallbackPossiblyUnderLock(SendOrPostCallback callback, Object state)   at System.Web.AspNetSynchronizationContext.CallCallback(SendOrPostCallback callback, Object state)   at System.Web.AspNetSynchronizationContext.Post(SendOrPostCallback callback, Object state)   at System.ComponentModel.AsyncOperation.Post(SendOrPostCallback d, Object arg)   at System.ComponentModel.AsyncOperation.PostOperationCompleted(SendOrPostCallback d, Object arg)   at System.Web.Services.Protocols.HttpWebClientProtocol.OperationCompleted(Object userState, Object[] parameters, Exception e, Boolean canceled)   at System.Web.Services.Protocols.SoapHttpClientProtocol.InvokeAsyncCallback(IAsyncResult result)   at System.Web.Services.Protocols.WebClientAsyncResult.Complete()   at System.Web.Services.Protocols.WebClientProtocol.ProcessAsyncResponseStreamResult(WebClientAsyncResult client, IAsyncResult asyncResult)   at System.Web.Services.Protocols.WebClientProtocol.ReadAsyncResponseStream(WebClientAsyncResult client)   at System.Web.Services.Protocols.WebClientProtocol.ReadResponseAsyncCallback(IAsyncResult asyncResult) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 72082da0  4000096        4         System.Int32  1 instance     1352 m_arrayLength 72082da0  4000097        8         System.Int32  1 instance     1351 m_stringLength 72081834  4000098        c          System.Char  1 instance       20 m_firstChar 72080b54  4000099       10        System.String  0   shared   static Empty    >> Domain:Value  01697520:01d801d0 1a421200:01d801d0 << 72081784  400009a       14        System.Char[]  0   shared   static WhitespaceChars    >> Domain:Value  01697520:01d80728 1a421200:01d8548c <<

• Anonymous
  February 10, 2010
  Wow.  Even after 4 years this article is still helping folks like me. Thanks Tess! Another new fan. :-)

• Anonymous
  March 03, 2010
  Hello Tess trust me - i'm almost never writing any comments! So this here is an extraordinary exception: Thank you, thank you, thank you! For "0xe0434f4d is the exception code for CLR (.net) exceptions" for ADPlus for windbg ... This really made my day!

• Anonymous
  March 28, 2010
  I'm very thankful for ALL the above information, however, im VERY computer illiterate and have no clue how to get rid of the error message saying UNHANDLED EXCEPTION. It appears everytime Im on the internet and try to close a window or windows b4 shutting down system. HELP!

• Anonymous
  March 16, 2011
  Hope someone can help me out on this.  I'm new to debugging and am desperately trying to make sense of all of this.  Here's what I've got so far.   Running adplus on my failing w3wp process, I received the following output files: FULLDUMP_FirstChance_epr_Process_Shut_Down_w3wp.exe__0878_2011-03-15_17-33-35-486_047c.dmp along with 30 or so MINIDUMP_FirstChance_av_AccessViolation_w3wp.exe__0878_2011-03-15_14-16-47-051_047c.dmp  files. Using windg on theFullDump, i executed !threads and got PDB symbol for mscorwks.dll not loaded ThreadCount: 27 UnstartedThread: 0 BackgroundThread: 27 PendingThread: 0 DeadThread: 0 Hosted Runtime: no                                      PreEmptive   GC Alloc           Lock       ID OSID ThreadOBJ    State     GC       Context       Domain   Count APT Exception XXXX    1  294 000e36a0   1808220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX    2  1b8 000f6010      b220 Enabled  00000000:00000000 000e8930     0 Ukn (Finalizer) XXXX    3  bb0 00113610    80a220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Completion Port) XXXX    4  214 00116d88      1220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX    5  a88 05d40ae0   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX    6  80c 05d75c38   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX    7  c28 05d709d8   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX    8  5c0 05e1b008   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX    a  780 05e1ec70       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX    d  dd0 0bf59e78   180b220 Enabled  00000000:00000000 109b4460     1 Ukn (Threadpool Worker) XXXX    e  3dc 0bf4d4b0   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX    f  490 0bf5a248   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX   10  3c4 0bf92900   880a220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Completion Port) XXXX   12  454 0bf80408       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX   14  e74 0bf9b1d8   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX   16  124 0c00d270       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX   17  d38 0c022738       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX   18  d7c 0c080cb0       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX   13  460 0c0a31c0       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX    c  de4 10989598       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX   15 1700 0bf8b078   200b220 Enabled  00000000:00000000 109b4460     0 Ukn XXXX    9  cf4 109891c8   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX    b 179c 0c0a3590   180b220 Enabled  00000000:00000000 000e8930     0 Ukn (Threadpool Worker) XXXX   19 1350 0bfdca88   180b220 Disabled 00000000:00000000 109b4460     1 Ukn (Threadpool Worker) System.StackOverflowException (026c106c) XXXX   11 1740 0c068d68       220 Enabled  00000000:00000000 000e8930     0 Ukn XXXX   1a 1144 05e1cdb0   200b220 Enabled  00000000:00000000 109b4460     1 Ukn XXXX   1b 1094 108ca1b0       220 Enabled  00000000:00000000 000e8930     0 Ukn then !do 026c106c which resulted in Name: System.StackOverflowException MethodTable: 04930dd8 EEClass: 0475262c Size: 72(0x48) bytes (C:WINDOWSassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 04930b24  40000b5        4        System.String  0 instance 00000000 _className 0492ff98  40000b6        8 ...ection.MethodBase  0 instance 00000000 _exceptionMethod 04930b24  40000b7        c        System.String  0 instance 00000000 _exceptionMethodString 04930b24  40000b8       10        System.String  0 instance 00000000 _message 0492a480  40000b9       14 ...tions.IDictionary  0 instance 00000000 _data 04930cb8  40000ba       18     System.Exception  0 instance 00000000 _innerException 04930b24  40000bb       1c        System.String  0 instance 00000000 _helpURL 04930740  40000bc       20        System.Object  0 instance 00000000 _stackTrace 04930b24  40000bd       24        System.String  0 instance 00000000 _stackTraceString 04930b24  40000be       28        System.String  0 instance 00000000 _remoteStackTraceString 04932d70  40000bf       34         System.Int32  1 instance        0 _remoteStackIndex 04930740  40000c0       2c        System.Object  0 instance 00000000 _dynamicMethods 04932d70  40000c1       38         System.Int32  1 instance -2147023895 _HResult 04930b24  40000c2       30        System.String  0 instance 00000000 _source 049333ec  40000c3       3c        System.IntPtr  1 instance        0 _xptrs 04932d70  40000c4       40         System.Int32  1 instance -532459699 _xcode But what do I do with a _remoteStackTraceString of 00000000?  What does this mean?  Any help would be GREATLY appreciated. Thanks, JP

• Anonymous
  March 16, 2011
  Hi JP, Stackoverflows are a bit special in the sense that they are only 1st chance exceptions even though they are "fatal" which means that you wont automatically get dumps on the stackoverflow. Try following the blogs.msdn.com/.../net-debugging-demos-lab5-crash-review.aspx walkthrough and get a dump with the unknonwn.cfg attached to that post to get a dump of the actual stackoverflow to see if you have some infinite recursion going on. Tess

• Anonymous
  April 13, 2011
  Hey Tess My app server has frequent w3wp crashes and I got dumps from Debugdiag for the 2nd chance exception for the crashing w3wp process but dont know how to do drill down furhter. Can I have your thoughts about this? Report for w3wp__PID__6676__Date__04_14_2011__Time_04_19_20AM__724__Second_Chance_Exception_E0434F4D.dmp Type of Analysis Performed   Crash Analysis Operating System   Windows Server 2003 Service Pack 2 Number Of Processors   2 Process ID   6676 Process Image   c:WINDOWSsystem32inetsrvw3wp.exe System Up-Time   13 day(s) 00:43:04 Process Up-Time   07:18:09 Thread 19 - System ID 3948 Entry point   mscorwks!Thread::intermediateThreadProc Create time   4/13/2011 9:02:01 PM Time spent in user mode   0 Days 0:0:39.93 Time spent in kernel mode   0 Days 0:0:1.671 Function     Arg 1     Arg 2     Arg 3   Source kernel32!RaiseException+3c     e0434f4d     00000001     00000001     mscorwks!RaiseTheExceptionInternalOnly+2a8     26d6d490     00000000     00000000     mscorwks!RaiseTheException+4e     26d6d490     00000000     0725f954     mscorwks!RaiseTheException+c0     00000000     069519e0     ce105099     mscorwks!RealCOMPlusThrow+30     26d6d490     00000000     0725f960     mscorwks!RealCOMPlusThrow+d     26d6d490     88bd0db9     79f50648     mscorwks!Thread::RaiseCrossContextException+41f     00000000     0725f998     0725fa08     mscorwks!Thread::DoADCallBack+2a2     00000009     79ec434e     0725fb0c     mscorwks!Thread::DoADCallBack+310     0725fb0c     0725fab8     79fa6abb     mscorwks!Thread::ShouldChangeAbortToUnload+e3     0725fb0c     88bd0fd9     00000001     mscorwks!Thread::ShouldChangeAbortToUnload+30a     0725fb0c     00000009     00000000     mscorwks!Thread::ShouldChangeAbortToUnload+33e     00000009     79f47b65     00000000     mscorwks!ManagedThreadBase::ThreadPool+13     00000009     79f47b65     00000000     mscorwks!ManagedPerAppDomainTPCount::DispatchWorkItem+e9     00000000     00000000     77e619d1     mscorwks!ThreadpoolMgr::ExecuteWorkRequest+af     88bd08cd     00000000     79ec47b1     mscorwks!ThreadpoolMgr::WorkerThreadStart+20b     00000000     00000000     0725fcb8     mscorwks!Thread::intermediateThreadProc+49     06934538     00000000     00000000     kernel32!GetModuleHandleA+df     79f7571f     06934538     00000000     In w3wp__PID__6676__Date__04_14_2011__Time_04_19_20AM__724__Second_Chance_Exception_E0434F4D.dmp the assembly instruction at kernel32!RaiseException+3c in C:WINDOWSsystem32kernel32.dll from Microsoft Corporation has caused a CLR Exception of type (System.NullReferenceException) on thread 19 This exception originated from mscorwks!RaiseTheExceptionInternalOnly+2a8. Module Information Image Name: C:WINDOWSsystem32kernel32.dll   Symbol Type:  Export Base address: 0x77e40000   Time Stamp:  Sat Mar 21 10:08:26 2009   Checksum: 0x00101b44   Comments:   COM DLL: False   Company Name:  Microsoft Corporation ISAPIExtension: False   File Description:  Windows NT BASE API Client DLL ISAPIFilter: False   File Version:  5.2.3790.4480 (srv03_sp2_gdr.090321-1244) Managed DLL: False   Internal Name:  kernel32 VB DLL: False   Legal Copyright:  © Microsoft Corporation. All rights reserved. Loaded Image Name:  kernel32.dll   Legal Trademarks:   Mapped Image Name:     Original filename:  kernel32 Module name:  kernel32   Private Build:   Single Threaded:  False   Product Name:  Microsoft® Windows® Operating System Module Size:  1.01 MBytes   Product Version:  5.2.3790.4480 Symbol File Name:  kernel32.dll   Special Build:  & Thnks SP

• Anonymous
  April 13, 2011
  Have you tried following the steps in the article, dumping out the exception etc.?  that should give you the callstack of the place where you got the exception

• Anonymous
  April 18, 2011
  Hey Tess, Tried debugging with windbg and got the below info but its not suggesting anything wrong about ths app, What do you think? Thanks for ur help in advance. 0:018> !threads ThreadCount: 32 UnstartedThread: 0 BackgroundThread: 19 PendingThread: 0 DeadThread: 12 Hosted Runtime: no                                      PreEmptive   GC Alloc           Lock       ID OSID ThreadOBJ    State     GC       Context       Domain   Count APT Exception  11    1 149c 000d8f68   1808220 Enabled  00000000:00000000 000d5a90     0 MTA (Threadpool Worker)  13    2 1988 000e4ef8      b220 Enabled  00000000:00000000 000d5a90     0 MTA (Finalizer)  14    3 1d24 000fd988    80a220 Enabled  00000000:00000000 000d5a90     0 MTA (Threadpool Completion Port)  15    4 1cd8 00100fd0      1220 Enabled  00000000:00000000 000d5a90     0 Ukn   9    5 18b0 0012dbe8   180a220 Enabled  00000000:00000000 000d5a90     0 MTA (Threadpool Worker)  17    7 15a8 05780b00   180b220 Enabled  00000000:00000000 000d5a90     0 MTA (Threadpool Worker)  18    8  7ac 0579f660      b020 Enabled  1cee7ba8:1cee937c 000d5a90     0 MTA System.Runtime.Serialization.SerializationException (1cee606c)  20    d 1774 058519a0   200b220 Enabled  00000000:00000000 057fc170     0 MTA  25   20 1ba8 0832dc38   200b220 Enabled  00000000:00000000 112b5688     0 MTA   3   12 18d4 113a15f0       220 Enabled  00000000:00000000 000d5a90     0 Ukn   2   1b 1818 000fec40       220 Enabled  00000000:00000000 000d5a90     0 Ukn  27   1c 1b8c 11560810   a80b220 Enabled  00000000:00000000 00101710     0 MTA (Threadpool Completion Port)  28   10 1ce0 115b4b78   200b220 Enabled  00000000:00000000 11547d50     0 MTA  29    e 1700 1687b9a8   200b220 Enabled  00000000:00000000 11547d50     0 MTA  30    b 17f0 1154a0a8   200b220 Enabled  00000000:00000000 11547d50     0 MTA   4   17 19ac 113fa338       220 Enabled  00000000:00000000 000d5a90     0 Ukn  31   29  e98 16a202d8   880b220 Enabled  00000000:00000000 000d5a90     0 MTA (Threadpool Completion Port)  33   2d 1c14 16a0f140   180b220 Enabled  00000000:00000000 000d5a90     0 MTA (Threadpool Worker) XXXX   30    0 1689eef0      9820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   2f    0 1696e880   8801820 Enabled  00000000:00000000 000d5a90     0 Ukn (Threadpool Completion Port) XXXX   27    0 1151caa8     10820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX    a    0 113788e8     10820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   2c    0 114a4a78     10820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   34    0 168b2680     10820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   38    0 16910868     10820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   33    0 168e0588     10820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   16    0 16959748     10820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   13    0 1685d9d0      9820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   21    0 0583da00      9820 Enabled  00000000:00000000 000d5a90     0 Ukn XXXX   1d    0 057b9bc0      9820 Enabled  00000000:00000000 000d5a90     0 Ukn  43   2a 1f08 16a1f390   200b220 Enabled  00000000:00000000 00101710     0 MTA  44   2e   fc 168191a0   200b220 Enabled  1ce26ce8:1ce28a18 00101710     0 MTA 0:018> !do 1cee606c Name: System.Runtime.Serialization.SerializationException MethodTable: 79313888 EEClass: 790e37d4 Size: 72(0x48) bytes (C:WINDOWSassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 79330ac4  40000b5        4        System.String  0 instance 1cee60c4 _className 7932ff38  40000b6        8 ...ection.MethodBase  0 instance 00000000 _exceptionMethod 79330ac4  40000b7        c        System.String  0 instance 1cee6d68 _exceptionMethodString 79330ac4  40000b8       10        System.String  0 instance 1cee6240 _message 7932a420  40000b9       14 ...tions.IDictionary  0 instance 00000000 _data 79330c58  40000ba       18     System.Exception  0 instance 00000000 _innerException 79330ac4  40000bb       1c        System.String  0 instance 00000000 _helpURL 793306e0  40000bc       20        System.Object  0 instance 00000000 _stackTrace 79330ac4  40000bd       24        System.String  0 instance 00000000 _stackTraceString 79330ac4  40000be       28        System.String  0 instance 1cee73a0 _remoteStackTraceString 79332d10  40000bf       34         System.Int32  1 instance        0 _remoteStackIndex 793306e0  40000c0       2c        System.Object  0 instance 00000000 _dynamicMethods 79332d10  40000c1       38         System.Int32  1 instance -2146233076 _HResult 79330ac4  40000c2       30        System.String  0 instance 1cee7250 _source 7933338c  40000c3       3c        System.IntPtr  1 instance        0 _xptrs 79332d10  40000c4       40         System.Int32  1 instance        0 _xcode 79330ac4  4000e4d      2a8        System.String  0   shared   static _nullMessage    >> Domain:Value  000d5a90:1ceb63c8 00101710:NotInit  057fc170:NotInit  058058a8:NotInit  05862878:NotInit  112b5688:NotInit  114ab458:NotInit  11547d50:NotInit  168b6648:NotInit  << 0:018> !do 1cee73a0 Name: System.String MethodTable: 79330ac4 EEClass: 790ed65c Size: 2054(0x806) bytes (C:WINDOWSassemblyGAC_32mscorlib2.0.0.0__b77a5c561934e089mscorlib.dll) String:    at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter)   at System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.Serialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter)   at System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck)   at System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Header[] headers, Boolean fCheck)   at System.Runtime.Remoting.Channels.CrossAppDomainSerializer.SerializeObject(Object obj, MemoryStream stm)   at System.AppDomain.Serialize(Object o)   at System.AppDomain.MarshalObject(Object o) Fields:      MT    Field   Offset                 Type VT     Attr    Value Name 79332d10  4000096        4         System.Int32  1 instance     1019 m_arrayLength 79332d10  4000097        8         System.Int32  1 instance     1018 m_stringLength 793317a4  4000098        c          System.Char  1 instance       20 m_firstChar 79330ac4  4000099       10        System.String  0   shared   static Empty    >> Domain:Value  000d5a90:025f1198 00101710:025f1198 057fc170:025f1198 058058a8:025f1198 05862878:025f1198 112b5688:025f1198 114ab458:025f1198 11547d50:025f1198 168b6648:025f1198 << 793316f4  400009a       14        System.Char[]  0   shared   static WhitespaceChars    >> Domain:Value  000d5a90:025f16f0 00101710:025f63c8 057fc170:028c21c0 058058a8:02a72e6c 05862878:02b413d4 112b5688:027944cc 114ab458:0315b5f4 11547d50:0301534c 168b6648:14a3be14 <<