Asp – IIS 7, ASP.NET: AccessViolationException

access-violationasp.netiis-7

What can be the reason of the following exception in ASP.NET application under IIS 7?
It is an unhandled exception that restarts the whole application.

Exception: System.AccessViolationException

Message: Attempted to read or write protected memory. This is often an indication that other memory has been corrupted.

StackTrace:

   in System.Web.Hosting.UnsafeIISMethods.MgdIsLastNotification(IntPtr pRequestContext, RequestNotificationStatus dwStatus)
   in System.Web.HttpRuntime.FinishRequestNotification(IIS7WorkerRequest wr, HttpContext context, RequestNotificationStatus& status)
   in System.Web.HttpRuntime.OnRequestNotificationCompletionHelper(IAsyncResult ar)
   in System.Web.HttpRuntime.OnRequestNotificationCompletion(IAsyncResult ar)
   in System.Web.HttpAsyncResult.Complete(Boolean synchronous, Object result, Exception error, RequestNotificationStatus status)
   in System.Web.HttpApplication.PipelineStepManager.ResumeSteps(Exception error)
   in System.Web.HttpApplication.ResumeStepsWaitCallback(Object error)
   in System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   in System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)
   in System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state)

[UPD]

System: Windows Web Server 2008 64-bit.

Application details: ASP.NET application that doesn't use pages architecture. It process requests using custom http sync and async handlers. There are also parallel threads from ThreadPool or created by Thread class are running.

Best Answer

A third-party ISAPI filter may cause this problem.

Related Solutions

C# – Login failed for user ‘IIS APPPOOL\ASP.NET v4.0’

Looks like it's failing trying to open a connection to SQL Server.

You need to add a login to SQL Server for IIS APPPOOL\ASP.NET v4.0 and grant permissions to the database.

In SSMS, under the server, expand Security, then right click Logins and select "New Login...".

In the New Login dialog, enter the app pool as the login name and click "OK".

enter image description here

You can then right click the login for the app pool, select Properties and select "User Mapping". Check the appropriate database, and the appropriate roles. I think you could just select db_datareader and db_datawriter, but I think you would still need to grant permissions to execute stored procedures if you do that through EF. You can check the details for the roles here.

C# – Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. The statement has been terminated

Looks like you have a query that is taking longer than it should. From your stack trace and your code you should be able to determine exactly what query that is.

This type of timeout can have three causes;

There's a deadlock somewhere
The database's statistics and/or query plan cache are incorrect
The query is too complex and needs to be tuned

A deadlock can be difficult to fix, but it's easy to determine whether that is the case. Connect to your database with Sql Server Management Studio. In the left pane right-click on the server node and select Activity Monitor. Take a look at the running processes. Normally most will be idle or running. When the problem occurs you can identify any blocked process by the process state. If you right-click on the process and select details it'll show you the last query executed by the process.

The second issue will cause the database to use a sub-optimal query plan. It can be resolved by clearing the statistics:

exec sp_updatestats

If that doesn't work you could also try

dbcc freeproccache

You should not do this when your server is under heavy load because it will temporarily incur a big performace hit as all stored procs and queries are recompiled when first executed. However, since you state the issue occurs sometimes, and the stack trace indicates your application is starting up, I think you're running a query that is only run on occasionally. You may be better off by forcing SQL Server not to reuse a previous query plan. See this answer for details on how to do that.

I've already touched on the third issue, but you can easily determine whether the query needs tuning by executing the query manually, for example using Sql Server Management Studio. If the query takes too long to complete, even after resetting the statistics you'll probably need to tune it. For help with that, you should post the exact query in a new question.

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