Re: Setting kernel data breakpoints on x86

From: Maneesh Soni
Date: Wed Nov 02 2005 - 02:16:47 EST


On Tue, Nov 01, 2005 at 04:30:26PM -0500, Alan Stern wrote:
> I'm trying to debug a rather difficult data-overwriting problem, and it
> would be a big help to be able to use a data breakpoint.
>
> Is there any easy way of doing this? I'd prefer not to use a kernel
> debugger, because the address of the breakpoint and the time when it's
> needed are determined dynamically.
>
> Does anybody have a little lightweight procedure for setting one of the
> x86's debug registers to point to a particular location in kernel memory
> space? I don't care if the whole system crashes when the debug exception
> occurs, just so long as I can get a stack trace and find out where the
> overwrite comes from.
>
>

Hi Alan

Probably watchpoint probes could be useful for this..

http://www.ussg.iu.edu/hypermail/linux/kernel/0508.3/1407.html

http://sourceware.org/ml/systemtap/2005-q3/msg00097.html

Thanks
Maneesh

--
Maneesh Soni
Linux Technology Center,
IBM India Software Labs,
Bangalore, India
email: maneesh@xxxxxxxxxx
Phone: 91-80-25044990
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