IE Crash with npctrl.dll division by zero error

[jwhitaker5]

We have one silverlight application that will crash Internet Explorer 8 and 9 with a division by zero error in npctrl.dll only when IE is run on a VM and the silverlight version is 5 (silverlight 4 doesn't crash on the VMs) . When we run IE with silverlight 5 on "bare" metal PC's and Servers we can not reproduce the crash. We've tested this with Workstation 8 and vShere 4 and 5 using Windows 2008 R2 servers and Windows 7 all 64bit.

The crashes don't occurr everytime, sometimes it take dozens of attempts to reproduce, they tend to occur when rapidly moving between tabs or when large record counts are returned to things like pull down lists.

Has anyone had similar issues with silverlight 5?  Could this be a driver issue? I didn't see anything in the KB or download that looked relevant.

[nielse]

Looks like a silverlight problem to me. We don't experience problems with silverlight 5 at the moment.

Does the crash happen immediately?

[jwhitaker5]

When tripped it crashes immediately. It only happens with one particular silverlight app of ours, but we can't reproduce it out side of a VMware VM.

[RobSiklos]

I can easily reproduce this on a vmware VM of Windows 2008 Server with a small test application.

The problem CANNOT be reproduced on physical hardware - only on vmware virtual machines.

It seems to be related to Silverlight applications using the so-called "client" network stack.

Sample project located here: http://www.siklos.ca/bugs/SLClientStackCrash.zip

References:

- https://connect.microsoft.com/VisualStudio/feedback/details/731642/silverlight-client-network-stack-...

- http://stackoverflow.com/questions/9382809/silverlight-5-debugging-npctrl-dll-crash/9812801#9812801

The problem also happens in Chrome and Firefox.

[kfoster]

We are seeing it as well on Workstation 8.  If we run it from a physical server no problems.  Next step is to try Virtual PC.

Have you entered a support ticket with VMware?

Thank you,

Kevin

[RobSiklos]

I don't pay vmware for support, so they say that I can only enter bugs using these forums.

Regardless, I think the bug is with Silverlight, since they are the ones who are dividing by zero.

I suggest you vote for the MS Connect issue I referenced in my last post.  Further, if you have any relationship with Microsoft, you could use that to bump the priority of the issue (which is probably very low at the moment).

[kfoster]

Thank you for the info! I will vote it up!

[jwhitaker5]

I have an open issue with Microsoft, it does look like their issue. Silverlight is trying to monitor download speeds to adjust buffer size, when it crashes the start and end times for download it timed are the same, so to figure the buffer they must be dividing by end time - start time. That's what I have from MS so far, no fix or ETA for one yet.

[kfoster]

Thank you for the update!

[kfoster]

We finally migrated our VM's to virtualbox and we haven't seen the problem. 

[MHALottering]

If you are running the silverlight application within a virtual machine, then you can try this if you get really really desperate and need to get it working.

If you are running your silverlight application and the data provider in the same web site or same process, try splitting them. Let me explain...

My application had 3 options, (1) DIRECT DATABASE CONNECTION (not applicable here), (2) WEB SERVICE or (3) HTTP aspx page.

Whenever I used options 2 and 3 but called the provider from within the same site, the application crashed soon. I noticed however that when I call the same (or different) web service hosted on another domain (cross-domains), then it doesn't crash.

My silverlight application relies heavily on threads running concurrently. I'm not sure if it has to do with the threads or why the w3w process and iexplore process don't work together well inside the VM.

I also got the "division by zero" error, but this was how I solved it. So, same code, same everything, except that the silverlight application and its hosted web site uses a different web site or web service as its data source (even if that data source web site was on the same virtual machine)

Does this make sense?

So S/L application running in http://localhost/app.aspx uses a WCF service running in https://itisqa-d1/folder1/service1.svc. And in this case the itisqa-d1 and localhost may or may not be the same machine, as long as they are running in seperate app domains or pools.

Martin

[patrickc]

Microsoft reported to us that a fix for this was included as part of the MS13-022 security release. You can download it at this link below.

https://support.microsoft.com/kb/2814124

[greenel]

Are you still seeing issues after applying the patch from Microsoft?  Is anyone?  If so, what other options have you tried to resolve the issue?