Question about kernel module debug

[Frank Ch. Eigler]

Yuxin_Zhuang@emc.com writes:

> I've installed systemtap 0.5.8 on RHEL4 with kernel 2.6.9-42. 

This is over a year old.  If you can, please upgrade to a later
systemtap build.  RHN should have 0.5.12 or even 0.5.14 by now.

> [...]  1. Is the 'debuginfo' of the module needed by systemtap is
> just the stuff created by gcc with option '-g'?

Yes.

> Will an additional '-O2' make a lot of difference?

It will make the debugging information somewhat less precise, giving
you fewer useful probe points.

> 2. I've put the '.ko' file which is built with options '-g -O2' under
> the proper search path and created a symbol link with the suffix
> '.ko.debug' to it. [...]

There should be no need for the .ko.debug file if the basic .ko file
was not stripped.  What does "readelf -S module.ko" say about .debug_*
sections?

- FChE