Recently I was dealing with a .NET windows service application that was failing when attempting to start the service. The exception showing up in the event log was the a “.NET Runtime 2.0 Error Reporting” unhandled framework of event type clr20r3, basically the framework logging that something is wrong (very wrong).

The actual exception logged was:

EventType clr20r3, P1 weauxpmmrp42zxajarbmdm5knch0ez4o, P2 0.4.112.0, P3 4ae90a3c, P4 nhibernate, P5 1.2.1.4000, P6 47c58d60, P7 ffd, P8 50, P9 nhibernate.mappingexception, P10 NIL.

This was annoying (to say the least) as the service had been running through all previous development and test installations, and was now failing in an environment where due to network restrictions it was not possible to debug with studio. However annoying the problem was, it was there and had to be solved.

With windows services there are ways to hook up a debugger when running or on start try to help identify issues, this KB article explains how to do this http://support.microsoft.com/kb/824344.

In this case however we had a crashing service, so it seemed to make sense to capture the crash for investigation. Using the debugging tools (http://www.microsoft.com/whdc/DevTools/Debugging/default.mspx), specifically the script adplus.vbs (http://msdn.microsoft.com/en-us/library/cc265629.aspx) it is possible to create a memory dump of the application state at crash. It was a bit of a race situation (and I am sure there are better ways), but it was simple to start the service then run the adplus command line to generate the crash dump. So using the command:

With –crash being self explanatory, –quiet to make start up quick (it was a race after all), –FullOnFirst to capture full dumps for all exceptions and –pn to identify the process name to hook. Once the adplus script starts it attaches to the process and produces a dump when the application fails.

There are loads of articles about how to read and deal with dump files a basic start is here http://support.microsoft.com/kb/315263, and whilst biased toward ASP.NET the debugging series by Tess Ferrandez at http://blogs.msdn.com/tess/pages/net-debugging-demos-information-and-setup-instructions.aspx is a great place to get introduced to the tools and techniques.

In this case the issue was identified from the information returned from the simple command “!analyze –v” on Windbg (more info on available commands can be found at http://windbg.info/doc/1-common-cmds.html). This issue was a pretty stupid simple one, our service was using nhibernate over an Oracle database using the Oracle Data Access Client. The ODAC is only delivered (at version 11.1.0.7.20) with a 32bit implementation, but the release config build of the service was not restricted to 32 bits - and so was throwing a bad image format exception on the ODAC dll. A quick change to this implementation using corflags /32BIT+, and a fix to the release configuration solved this.