Re: Inserting a probe point into a module?

[William Cohen <wcohen at redhat dot com>]

Nathan DeBardeleben wrote:
> I'm sure this has been asked before but I didn't see it looking around.  
> Can I use systemtap / kprobes to probe a point that's in a module that's 
> been isnmodded?  Something I really need to do is probe points in an 
> InfiniBand driver.  I have the network driver module source, so I know 
> where I want to probe... but just not sure if it's possible.
>
> My instinct is that it might not be possible because we don't have the 
> appropriate kernel-debuginfo for this module... or can I create it somehow?
>
> Thanks!

You can probe modules installed in the kernel. You need to used "probe 
module("mod").function("func"). Assuming that the module has been built 
with debugging information this should work.

The debuginfo rpm is needed for the normal kernel because the debug 
information isn't included in the normal vmlinuz and is stripped out of 
the modules during the normal RPM build process. If you are building the 
module locally, it should still have that information in the module.

-Will