IIS 6 Hangs , then app pool resets. IIS Debug Diag Dump Attached

Question

IIS 6.0 Hangs, then the app pool resets after approximately 3 minutes. This is an ASP site, upon reset it functions great for a few seconds, then hangs. All other App Pools on this instance of IIS 6 function correctly. There do not appear to be any performance issues with this machine. I took a memory dump using IIS Debug Diagnostics, and this is the rendered analysis. Can anyone please lend some support?

Analysis Summary
Type Description Recommendation Warning Detected possible blocking or leaked critical section at ntdll!LdrpLoaderLock owned by thread 24 in w3wp.exe__SupportSiteAppPool__PID__3960__Date__07_23_2009__Time_02_22_36PM__551__Manual Dump.dmp

Impact of this lock

66.67% of executing ASP Requests blocked

22.58% of threads blocked

(Threads 6 22 23 27 28 29 30)

The following functions are trying to enter this critical section

ntdll!LdrLockLoaderLock+133

ntdll!LdrpGetProcedureAddress+128

ntdll!LdrpInitializeThread+68

The following module(s) are involved with this critical section

C:\WINDOWS\system32\ntdll.dll from Microsoft Corporation The entry-point function for a dynamic link library (DLL) should perform only simple initialization or termination tasks, however this thread (24) is loading a dll using the LoadLibrary API. Follow the guidance in the MSDN documentation for DllMain to avoid access violations and deadlocks while loading and unloading libraries.

Please follow up with the vendor Microsoft Corporation for C:\WINDOWS\system32\mscoree.dll

Warning Detected possible blocking or leaked critical section at asp!g_ViperReqMgr+2c owned by thread 8 in w3wp.exe__SupportSiteAppPool__PID__3960__Date__07_23_2009__Time_02_22_36PM__551__Manual Dump.dmp

Impact of this lock

6.45% of threads blocked

(Threads 7 9)

The following functions are trying to enter this critical section

asp!CViperActivity::PostAsyncRequest+72

The following module(s) are involved with this critical section

\?\C:\WINDOWS\system32\inetsrv\asp.dll from Microsoft Corporation The following vendors were identified for follow up based on root cause analysis

Microsoft Corporation

Please follow up with the vendors identified above Consider the following approach to determine root cause for this critical section problem: Enable 'lock checks' in Application Verifier Download Application Verifier from the following URL:

 Microsoft Application Verifier

Enable 'lock checks' for this process by running the following command:

 Appverif.exe -enable locks -for w3wp.exe

See the following document for more information on Application Verifier:

 Testing Applications with AppVerifier

Use a DebugDiag crash rule to monitor the application for exceptions

Answer 1

Given the information provided it sounds like a problem with the application itself rather than IIS. Have you made sure there aren't any crazy tight loops or excessive/extremely heavy DB loads, possibly some PInvoke calls or just something out of the ordinary for a webapp that are killing the application/runtime and causing the pool to die?

Answer 2

I think you should try some tools likes fiddler and other things.With that you can have exact idea what is taking time to load your site. From the log it seems that there is problem with the application itself. So don't use excessive loops, cache data from db and use and also don't store large object in session or application.

Answer 3

I hope you didn't just post your production password bro :).

I agree with Quintin, seems like something in the ADO provider is causing the failure.

Answer 4

Your ASP Classic App is failing because all threads are blocked. I suggest running Process Monitor on the web server to see what handles are taken up where. I don't see a lot of repetition in your stack trace that would indicate a problem with a particular dll.