Setting Exception._stackTrace value by reflexion causes a 'FatalExecutionEngineError'

[Arbiorix]

I need to set the value of the StackTrace property of an exception.

As this property has not setter, I do it by reflection on the private field _stackTrace.

When accessing the exception object, I get a FatalExecutionEngineError.
Any idea why?

Thank you.


Exception e = new Exception();
FieldInfo stackTraceFieldInfo = typeof(Exception).GetField("_stackTrace", BindingFlags.Instance | BindingFlags.NonPublic);
stackTraceFieldInfo.SetValue(e, serviceExceptionData.StackTrace);
...
Console.WriteLine(e)


FatalExecutionEngineError was detected
Message: The runtime has encountered a fatal error. The address of the error was at 0x79e7b217, on thread 0x14bc. The error code is 0xc0000005. This error may be a bug in the CLR or in the unsafe or non-verifiable portions of user code. Common sources of this bug include user marshaling errors for COM-interop or PInvoke, which may corrupt the stack.

[Plater]

You know you can just type cast any derrived exception type into its base Exception type?

Exception e = (Exception)serviceExceptionData;
Console.WriteLine(e)
 

[Arbiorix]

You know you can just type cast any derrived exception type into its base Exception type?

Exception e = (Exception)serviceExceptionData;
Console.WriteLine(e)
 

Would be easy..., but serviceExceptionData is just the object holding the StackTrace string I need to inject in the new exception. In my case, ServiceExceptionData does not derivate from Exception.

[Plater]

And the strack trace in that string does not match the stracktrace that would exist if you went "throw new Exception()" at the same time as that string was populated?

[Arbiorix]

And the strack trace in that string does not match the stracktrace that would exist if you went "throw new Exception()" at the same time as that string was populated?

I don't think this is a matter of 'Matching' or not.
When I do "Exception e = new Exception()", the StackTrace value is null.
Then, I set it to a valid StackTrace string. For example,

stackTraceFieldInfo.SetValue(e, Environment.StackTrace);

would produce the same problem.

[Plater]

Hmm, I guess the stacktrace value doesn't get populated until you "throw" it.
I am not sure why you cannot just set the value, possibly due to the way a debugger would interpret it, since it would use the stack trace to decide debugging information?
Was there anything on the net about the error message you got?

[Arbiorix]

...the way a debugger would interpret it, since it would use the stack trace to decide debugging information?

If I enclose the above code in a try-catch, and run it in non-debbuging mode, no exception is catched. The app simply crashes with the classical "SetExceptionStackTrace has encountered a problem and needs to close. We are sorry for the inconvenience. If you were in the middle of something ...."

Was there anything on the net about the error message you got?

I didn't find any relevant information. That's why I posted this as a question here.

But you remarks gave an idea: I will study what MSDN says about 'Diagnosing Errors with Managed Debugging Assistants'. If someone has already some experience with this kind of stuff, please don't hesitate to give me your comments!

[Arbiorix]

Ok, I got it.

The backing field of Exception.StackTrace is not _stackTrace but _stackTraceString.

Thanks Plater for your support.