Strange exceptions in .Net CF framework code under WinCE 6.0 R3

Answer 1

I think the message on your second trace is the most instructive

A native exception has occurred on BbCore.exe

It appears that it's a native exception not a managed exception that is taking down your product. Native exceptions are as a general rule not catchable by managed code. It is possible in certain cases but generally speaking native exceptions are fatal.

You can try to use the catch block for SEH exceptions and see if that works.

try { 
  ...
} catch { 

}

But in general if the native code is throwing your application is unstable and it should crash.

Answer 2

Turned out it was a buffer overrun error in native code. the C# code was calling into a method and passing a byte array with 8 elements. The C++ code was filling 6 bytes then overwriting another 6 with zeroes. This method got called quite a lot and every time it was overwriting 4 bytes of memory with zeroes. Doh!

That explains the utterly strange errors, probably was overwriting bits of the .Net framework in memory.

Gotta watch out for those interactions between managed and unmanaged code. Fortunately for me, the code in question wasn't mine.

(Not sure if I should accept my own answer as the answer since no one could have answered this without looking at our code base. Likewise I shouldn't mark JaredPar's answer as "the answer" since the problem was memory corruption, not really a native exception. I guess I'll post this anyway since maybe someone else will have a similar situation and maybe they'll look into interactions with native code. Admins: feel free to delete this thread if you think that's best.)