The OllyDbg 100 percent CPU problem - and its solution
dELTA <deltapoboxse> Monday, February 11 2008 15:11.52 CST


A problem in OllyDbg 1.10 is that it takes up 100% CPU as soon as it's debugging a target and the target is running on its own (i.e. after pressing F9 in OllyDbg at some point).

If nothing else, it causes any laptop that you might be reversing on to lose much more battery life than necessary, and also to sound like a jet plane due to constant maximum fan rotation.

The problem was discussed, analyzed, found and solved (by means of an OllyDbg patch) over at the RCE Forums earlier today, and I can recommend at least anyone who normally reverses on a laptop to take a look at it:

http://www.woodmann.com/forum/showthread.php?t=11302

The solution has also already been packaged into an OllyDbg plugin (by blurcode), which you can find in the Collaborative RCE Tool Library, at:

http://www.woodmann.com/collaborative/tools/index.php/CPU_Initialization_Patch

Comments
GynvaelColdwind Posted: Tuesday, February 12 2008 01:15.42 CST
Didn't know that. Thanks for sharing, it will come in handy ;>

MohammadHosein Posted: Tuesday, February 12 2008 16:17.01 CST
VCL , by nature , is not thread-safe and playing with UI elements inside the main loop/thread is always causing these issues , thanks for the patch

dELTA Posted: Wednesday, February 13 2008 06:51.27 CST
Actually, it had nothing to do with VCL, but was rather just due to bad design of the OllyDbg code. We're glad our analysis and patch could be of use anyway!