IIS errors from upgrade to net 4

Question

In October, we upgraded one of our sites (in IIS 6) from .net 3.5 to .net 4.0. Since then, we receive the following warning and error every day:

Attention:

ISAPI 'C: \ Windows \ microsoft.net \ Framework \ v4.0.30319 \ aspnet_isapi.dll' stated the following reason as unhealthy: "Deadlock detected."

Mistake:

It is not possible to run two different versions of ASP.NET in the same IIS process. Please use the IIS Administration Tool to reconfigure your server to run the application in a separate process.

We tested all the applications and ensured that they work in the correct versions of ASP.NET, as well as in our own application pools.

We looked at the IIS logs while recording errors, but this does not give any indication of the problem. Is there a tool available that can give us more information about which application is causing errors and what is happening at that time?

Answer 1

The discussion here may be useful to you:

You can configure the application pool for orphaned workflow, and not kill it when this condition happens - you can use adplus to collect a hang up dump of the workflow, which can be analyzed to find out what is inhibited in this process.

(...)

This means that asp.net thrads have not returned from any activity that they have been doing for a very long time, and asp.net has ended threads - this usually indicates a dead end. This kb also talks about how to create dumps for analysis for this condition.

Answer 2

I had the same error, and this was due to the special .NET 2.0 error page that my .NET 4.0 application linked to.

I created a custom error page that was developed in .NET 2.0, and was applied at the top level of the IIS website.

The .NET 4.0 application used the unique MVC URL routing scheme, and for some reason, it was this application that continued to block, and eventually these deadlock errors occurred.

I got rid of the custom error page setup that pointed to the .NET 2.0 web page and switched it to the default static error “Not Found”. I restarted the application pool and the web page started working without problems.

Hope this helps someone else.

http://adamantinewolverine.blogspot.kr/2012/10/running-iis6-in-32-bit-mode-on-64bit.html