VS2008 protected memory read exception

[JonathanN]

Hi Paul,

At this point, we are not sure as to why the problem is occurring. I tested your application on a few other machines and laptops and was unable to reproduce the problem. We are working on the issue and trying to decide what steps we need to take next. Our assemblies are obfuscated which does make troubleshooting on your end tougher.  I'lll let you know if you need to do anything to help us out.

The best option (which I know you have tried) would be to reproduce the problem on some VMImage that you could send us. But I know that's very unlikely.

Best Regards,

[JonathanN]

Hi Paul,

One thought we did have was maybe the behavior you are seeing is related to the Data Exection Prevention (DEP) setting that is enabled by default on Windows Vista.  This is only enabled if the processor supports this feature.  Try disabling DEP on the system by running the following command on the command line and then rebooting the machine.
bcdedit.exe /set {current} nx AlwaysOff


To restore DEP to the default setting, run the following command on the command line

bcdedit.exe /set {current} nx Optin

Also, if that doesn't work, would it be possible for you to set aside some machine that we could log into?

Best Regards,

[pbrown]

disabling DEP seems to work, I'll re-enable it later to make sure that the problem is still there.

However this isn't really something I want to have to ask clients to do if they happen to have a similar machine.

How would you propose to login to a machine ?

[JonathanN]

Hi Paul,

DEP is safe to turn off and you can actually do it per application by using the EditBin.exe tool that ships with VC. That tool is located in the C:\Program Files\Microsoft Visual Studio 8\VC\bin. So you would say something like:

EditBin <AssemblyPath> /NXCOMPAT:NO 

To turn it back on, you can just use /NXCOMPAT. 

This actually changes a bit on the EXE and thus your end-users will not have to mess with anything.

Now, we still want to get to the bottom of the issue by logging into your machine, installing some debug files and debugging some code. We would need some time on this in order to get everything setup. As far as logging into your machine, in the past, I have just used Remote Desktop, unless you have a better or preferred method.  It would be nice if you could just setup some machine that you don't currently need (i.e. I don't want to disrupt your development) and allow us to use that.

Anyway, once I have some more information on this, I will let you know.

Best Regards,

Message Edited by Jonathan N on 05-08-2008 01:37 PM

[pbrown]

RDP should be ok, it may require a 2 step process to get onto our DMZ.

Depending on what software you need on the machine (VS + components etc)  I could probably arrange for one that fails to be available

Thanks

Paul

[JonathanN]

Hi Paul,

Can you provide us with the CPU information on the PCs that fail?
Also, just to remind myself, on those systems that fail currently, are you using Measurement Studio 8.1.2 or 8.1.1?

Thanks,

Best Regards,

[pbrown]

the ones that have failed are all Centrino's running vista. My laptop is a Pentium M 780 and the others have been similar single core machines. And using 8.1.2

Paul

[JonathanN]

Hi Paul,

Well, I need a little more information about your CPU so I have attached software called cpu-z that I would like you to run. Please take a screenshot of the results and post that back. 

Also I would like you to do the following:

1. Set the polynomial order to less than 6 in your example
2. Run this example iteratively or insert a breakpoint after the call to force the analysis library to stay in memory. 
3. Go to C:\Program Files\National Instruments\Shared\MKL\MKL70 directory. Try to delete each dll. There should be several dlls that can not be deleted. Please send the dll names back. Warning: It's better to backup these dlls first in case you permanently delete them.

Thanks

Best Regards,

[pbrown]

Hi,

I set the power down to 5 and the breakpoint after the call to PolynomialFit (see screenshots in word doc) but could delete all of the files in the MKL directory.

Paul

[pbrown]

I had a local copy of the dll's in the bin directory (from trying on different machines). After removing these I get the following trying to delete the dlls when running

C:\Program Files\National Instruments\Shared\MKL\MKL70>del *.dll
C:\Program Files\National Instruments\Shared\MKL\MKL70\libguide40.dll
Access is denied.
C:\Program Files\National Instruments\Shared\MKL\MKL70\mkl_def.dll
Access is denied.
C:\Program Files\National Instruments\Shared\MKL\MKL70\mkl_lapack64.dll
Access is denied.
C:\Program Files\National Instruments\Shared\MKL\MKL70\mkl_p3.dll
Access is denied.
C:\Program Files\National Instruments\Shared\MKL\MKL70\mkl_p4.dll
Access is denied.

Paul