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 Forums >>  Debuggers  >>  How does one RE multitasking code?

Topic created on: April 17, 2009 13:35 CDT by Unknown .

Is there a source I can read on this subject?  With multicore CPUs all around us multi-tasking is gaining ground and I personally do not know how to RE a mt program.  I have one and when it is dealing with the multitasking parts I get lost.

  fintler     December 31, 2009 10:45.57 CST
You need to be more specific on what you're asking.

Reverse engineering a multithreaded program usually just requires building a nice (directed) graph of where threads are created, waiting, and joined. Keeping track of locks and how global memory is accessed would probably be useful as well. This can easily be accomplished with a debugger like gdb or whatever using the tools for breakpoints and switching between threads.

The first step in reverse engineering a multithreaded program may simply be the task of writing a program that uses threading or LWPs or whatever. You're really not going to be able to rip apart a program until you've built something similar yourself.

Also, you may want to look into what the word "multitasking" actually means. Start with researching how it works on a single CPU before you bother with muti-cpu/cores. Take a look at the difference between preemptive and cooperative multitasking. Take a look at the recent research done with the linux kernel process scheduler.

There's some great notes on concurrency and other nifty concepts at <http://www.cis.temple.edu/~ingargio/cis307/readings/index.html>. Take a close look at the notes on "test and set" as well as general atomicity of variables.

Also, you should come back with a snippet of assembly or whatever that you're not understanding and let us work through it as a group! Asking a question as vague as the one you asked isn't going to get you a very good answer. :)

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