Tag Archives: WinDbg

.NET 4.0 Type Equivalence causes BadImageFormatException

By ian | Published: April 23, 2010

Interop assemblies containing certain constructs will cause a BadImageFormatException in .NET 4.0

Posted in .NET, COM, Debugging, WinDbg, Windows | Also tagged , , , , , | 6 Comments

Modifying the VC runtime to get better heap allocation stack traces

By ian | Published: March 17, 2010

Heap allocation stack traces are useless when using certain versions of the MSVC runtime. Is it possible to modify and rebuild MSVCR80 to avoid this?

Posted in Debugging, Software Development, WinDbg, Windows | Also tagged , , | Leave a comment

Beware of using stack-based COM objects from .NET

By ian | Published: January 21, 2010

COM objects that don’t have the expected lifetime can cause chaos when combined with .NETs garbage collection system.

Posted in .NET, COM, Debugging, Software Development, WinDbg | Also tagged , , , , , | Leave a comment

Getting IUnknown from __ComObject

By ian | Published: September 3, 2009

How do you find the unmanaged COM object that’s being referenced by a .NET object?

Posted in .NET, COM, Debugging, Software Development, WinDbg, Windows | Also tagged , , , | 4 Comments

Finding the largest free block of address space

By ian | Published: August 21, 2009

I’ve been seeing problems recently with fragmented virtual address space. During the lifetime of a process, bits and pieces of memory are allocated throughout the 2GB 32-bit address space to such an extent that large contiguous blocks of free space are no longer available. If anything subsequently requires a large block of memory (like, for [...]

Posted in Software Development, WinDbg, Windows | Also tagged , , , , | 2 Comments

Diagnosing out of memory errors with VMMap

By ian | Published: July 28, 2009

VMMap is a new tool from Mark Russinovich et al that’s very useful for diagnosing virtual memory/address space exhaustion issues. I describe it here, and give some information that should help you interpret what it reports.

Posted in Debugging, Software Development, WinDbg, Windows | Also tagged , , , | 2 Comments

WinDbg !locks command broken

By ian | Published: June 3, 2009

It seems that the extremely useful !locks command is broken in 6.11.1.40x, the current and previous release of WinDbg from the debugging tools for Windows.
You’ll get errors like:

0:007> !locks
NTSDEXTS: Unable to resolve ntdll!RTL_CRITICAL_SECTION_DEBUG type
NTSDEXTS: Please check your symbols

The suggested solution seems to be to roll-back to version 6.10.3.233, available from here, or you can just [...]

Posted in Debugging, WinDbg | Also tagged | 2 Comments

Troubleshooting an InvalidProgramException

By ian | Published: October 1, 2008

One of the developers who uses the .NET/COM interop DLL that I wrote recently informed me that when they used it in a certain way, they would get a fatal System.InvalidProgramException. Nasty. So I set about seeing how I could find out exactly why this was happening: here are the gory details…
To spoil the ending [...]

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