Thread.Abort in ASP.NET app causes w3wp.exe to crash

Question

Please do not set duplicate flag on this qustion - it is not about "why ThreadAbortException occurs", it is about "why w3wp.exe process terminates after ThreadAbortException".

Let's say we have simple web application with following code sample:

protected void Page_Load(object sender, EventArgs e)
{
    Response.Redirect("http://google.com");
}

Which by fact means something like (see Is Response.End() considered harmful?):

protected void Page_Load(object sender, EventArgs e)
{
    ...response write some data...
    System.Threading.Thread.CurrentThread.Abort();
}

On my machine (Windows 10 Pro + IIS) this code leads to IIS pool process termination with error code 0x0 (redirect not performs). On other machines (which is NOT Windows 10) this code only generates ThreadAborted exception, but process continue working (redirect performs).

Can someone check this sample and explain what is going on?

UPDATE Here some windows event logs related to this issue.

log #1

An unhandled exception occurred and the process was terminated.

Application ID: /LM/W3SVC/1/ROOT/AS

Process ID: 6700

Exception: System.Threading.ThreadAbortException

Message: Thread was being aborted.

StackTrace: at System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) at System.Web.Hosting.PipelineRuntime.ProcessRequestNotificationHelper(IntPtr rootedObjectsPointer, IntPtr nativeRequestContext, IntPtr moduleData, Int32 flags) at System.Web.Hosting.PipelineRuntime.ProcessRequestNotification(IntPtr rootedObjectsPointer, IntPtr nativeRequestContext, IntPtr moduleData, Int32 flags)

log #2

Faulting application name: w3wp.exe, version: 10.0.10240.16384, time stamp: 0x559f3dad
Faulting module name: KERNELBASE.dll, version: 10.0.10240.16384, time stamp: 0x559f3b2a
Exception code: 0xe0434352
Fault offset: 0x000b3e28
Faulting process id: 0x1a2c
Faulting application start time: 0x01d0e4b1b3ed01cb
Faulting application path: C:\WINDOWS\SysWOW64\inetsrv\w3wp.exe
Faulting module path: C:\WINDOWS\SYSTEM32\KERNELBASE.dll
Report Id: 23b5298d-3b36-49c7-a294-de9c864b703f
Faulting package full name: 
Faulting package-relative application ID: 

Supertonic

What behaviour are you trying to achieve by using Thread.Abort() here? – Fleshy

What .net version are you using? – Housekeeping

@peer, .Net v4.0.30319 – Supertonic

@Nanhydrin, Thread.Abort is just an example to show what is going on inside Response.Redirect, i.e. Response.Redirect() calls Response.End() and then calls Thread.Abort() (see #1088277) – Supertonic

I've seen this issue, too, specifically after installing .Net 4.6 (and no I don't know why yet). Even though my project didn't target 4.6, that is the framework that will be used as indicated by this link: developers.slashdot.org/story/15/07/28/160255/… – Camphor

@manderson, my project also uses old framework v4.0 and v4.6 is installed. Besides this, I've noticed same behaviour on Windows 8.1 with latests updates (but dont remember if there were 4.6) – Supertonic

I'm having the exact same problem, but my colleagues can run the exact same code without issues. – Lucilius

@erikkallen, same story. I just was the first one who updated OS from W8.1 to W10. But now I'm definitely not alone )) – Supertonic

I'm on Windows 7 (SP1), though. – Lucilius

possible duplicate of Why Response.Redirect causes System.Threading.ThreadAbortException? – Cottontail

@Cottontail No, that is not a duplicate. The other question is about why Response.End causes a ThreadAbortException, this one is about why a ThreadAbortException causes w3wp to fail with a Win32Exception – Lucilius

@AlekDepler - can you post the windows event log message as well? I also retagged the question. The "response redirect / thread abort" has come up so many times, this just looked like the same thing that has been reported many times. – Cottontail

@erikkallen, do you have .NET Framework 4.6 installed on your machine? What is difference between your machine and your colleagues? Do you have latests MS updates installed? – Supertonic

Have you installed the RyuJIT update KB for the optimization bug, or any workarounds to avoid it before? This article comments mention the same kind of activity when using a workaround. blogs.msdn.com/b/dotnet/archive/2015/07/28/… – Cottontail

I also had this problem with a 4.0 Framework website on my localhost PC which is now on Windows 10. Adding the "false" second parameter got the Redirect to work (see Alek's solution below about returning). Targeting the site to Framework 4.5.2 or 4.6 did not help. – Leff

@Supertonic Were you able to find a solution to this issue? I am seeing the same issue where ThreadAbortException causes a crash in w3wp, when theoretically it shouldn't. – Rucksack

Answer 1

I was able to reproduce the issue on Server 2008r2 with .NET 4.6 installed.

I suspect it was the same problem the rest of you are running into; ThreadAbortExceptions killing the application pool in the event log (though any unhandled exception would cause the issue in my case; but that may just be a global exception handler catching it and finishing with a Response.End or Redirect). The dump stacktrace also matches the one in Ian's answer.

There was a MS Connect ticket opened for the issue, and a recent KB hotfix resolves the issue for me.

Connect Article: https://connect.microsoft.com/VisualStudio/feedback/details/1605438/disabling-ryujit-breaks-asp-net

KB Hotfix: https://support.microsoft.com/en-us/kb/3098786

Dread

Answer 2

So far I have the only one solution:

    static class WebExtensions
    {
        public static void EndSafe(this HttpResponse response)
        {
            response.Flush();
            response.SuppressContent = true;
            HttpContext.Current.ApplicationInstance.CompleteRequest();
        }

        public static void RedirectSafe(this HttpResponse response, string url)
        {
            response.Redirect(url, false);
            HttpContext.Current.ApplicationInstance.CompleteRequest();
        }
    }

This is however forces me to ensure that there will be no code executed after it:

...some code
response.RedirectSafe(url);
return; //<-- important
...some more code

Pay attention, that only "return" is not enough in some cases (for example with recursive calls) and in some cases you may need to avoid using "return" (with try-finally constructions)

Supertonic

I think this only masks the problem, and you're right to question why the ThreadAbortException is crashing all the way out to w3wp.exe. I'm currently diagnosing a similar issue after upgrading to .NET 4.6. – Gladsome

Ran into the same thing after upgrading to IIS 8 and .NET 4.6. Response.Redirect() when called inside of Application_BeginRequest made the whole process crash. This code fixed it. It had not been a problem for us on IIS 7. – Selfabsorbed

Answer 3

I ran into this exact same problem on Windows 8.1 today, after rebooting to install Windows Updates.

The problem was that I had manually disabled RyuJIT in the Registry, due to this issue, by adding the useLegacyJit DWORD and setting it to 1 (see Method #3). But one of the updates created the UseRyuJIT key in the same location and set it to 1 as well, and this apparently confused ASP.NET horribly.

The solution was to set useLegacyJit to 0 and issue an iisreset. After that, all is good in the world.

WinDbg's !clrstack showed the following frames when I debugged the w3wp.exe dump. Perhaps this will help others with the same error who are Googling for a solution:

000000ef9892be98 00007ffa0e2d1fea [HelperMethodFrame: 000000ef9892be98] 
000000ef9892bf80 00007ff99d776588 System.Web.Hosting.PipelineRuntime.ProcessRequestNotification(IntPtr, IntPtr, IntPtr, Int32)
000000ef9892df90 00007ff9fc172345 [FaultingExceptionFrame: 000000ef9892df90] 
000000ef9892e490 00007ff99d7796c0 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(System.Web.Hosting.IIS7WorkerRequest, System.Web.HttpContext)
000000ef9892e520 00007ff99d777377 System.Web.Hosting.PipelineRuntime.ProcessRequestNotificationHelper(IntPtr, IntPtr, IntPtr, Int32)
000000ef9892e700 00007ff99d77655a System.Web.Hosting.PipelineRuntime.ProcessRequestNotification(IntPtr, IntPtr, IntPtr, Int32)
000000ef9892e740 00007ff99d775c11 DomainNeutralILStubClass.IL_STUB_ReversePInvoke(Int64, Int64, Int64, Int32)
000000ef9892ef58 00007ff9fc100b4e [InlinedCallFrame: 000000ef9892ef58] System.Web.Hosting.UnsafeIISMethods.MgdIndicateCompletion(IntPtr, System.Web.RequestNotificationStatus ByRef)
000000ef9892ef58 00007ff99d78cc1b [InlinedCallFrame: 000000ef9892ef58] System.Web.Hosting.UnsafeIISMethods.MgdIndicateCompletion(IntPtr, System.Web.RequestNotificationStatus ByRef)
000000ef9892ef30 00007ff99d78cc1b DomainNeutralILStubClass.IL_STUB_PInvoke
000000ef9892f000 00007ff99d77756c System.Web.Hosting.PipelineRuntime.ProcessRequestNotificationHelper(IntPtr, IntPtr, IntPtr, Int32)
000000ef9892f1e0 00007ff99d77655a System.Web.Hosting.PipelineRuntime.ProcessRequestNotification(IntPtr, IntPtr, IntPtr, Int32)
000000ef9892f220 00007ff99d775c11 DomainNeutralILStubClass.IL_STUB_ReversePInvoke(Int64, Int64, Int64, Int32)
000000ef9892f418 00007ff9fc100da3 [ContextTransitionFrame: 000000ef9892f418]

Blynn

Thanks for the stacktrace; that's what led me here and confirmed that other people are running into the same problem and I'm not crazy. – Dread

@Dread Glad I could help! – Blynn

Answer 4

I've been experiencing the same issue on Win7 SP1. Web app compiled targeting .net 4.5.2 and running on .net 4.6. And I haven't been messing with the useLegacyJit or useRyuJIT registry flags.

Turned out "Enable 32-Bit applications" was unnecessarily set to Enabled on my app domain. Disabling it fixed the problem.

Earring