Searching In Windbg

Ewald Cress shows us how to search for a four-byte pattern in the Windows debugger:

Cracking open Windbg on 2016 SP1 with the s command to look for byte patterns yielded nothing of value. Maybe something has changed with conventions or indirection? Nope, no joy in 2014 either.

In the end, it took the extremely brave step of RTFM, in this case the Windbg online help, to realise where I was going wrong. I was searching for a four-byte pattern by searching for doublewords. Sounds reasonable on the face of it, but what I had missed was that this specifically required the doublewords to be doubleword-aligned, i.e. starting on an address divisible by four. My method only had a 25% chance of working, so it’s sheer luck I ever got good results with it.

Changing to a byte search for four consecutive bytes gave me the non-aligned semantics my taste buds craved, and the results came pouring in.

This is in the context of gathering information on an uncommon wait type related to columnstore indexes.

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