Inserting a probe point into a module?

Inserting a probe point into a module?

[Nathan DeBardeleben]

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!

-- 
-- Nathan
Correspondence
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Nathan DeBardeleben, Ph.D.
Los Alamos National Laboratory
Parallel Tools Team
High Performance Computing Environments
phone: 505-667-3428
email: ndebard@lanl.gov
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Re: Inserting a probe point into a module?

[William Cohen]

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