Re: "No match for probe point" for syscall.open with tutorial example strace-open.stp

[David Smith <dsmith at redhat dot com>]

Fredy Neeser wrote:
> Hi,
>
> I am trying to use systemtap (20070818 snapshot) on an IA32 Core Duo system with
> Fedora Core 5 and a kernel which I built from vanilla 2.6.18 sources.

(Note that I've never used systemtap with a self-built kernel, but I'll 
take a stab at this anyway.)

... stuff deleted ...

> the next tutorial example
>
>         [root@mythen stap_tests]# stap -vvv strace-open.stp
>
> gives "No match for probe point" for syscall.open:
>
> SystemTap translator/driver (version 0.6/0.128 built 2007-08-23)
> Copyright (C) 2005-2007 Red Hat, Inc. and others
> This is free software; see the source for copying conditions.
> Created temporary directory "/tmp/stapyFwODp"
> Searched '/usr/local/share/systemtap/tapset/i686/*.stp', found 1
> Searched '/usr/local/share/systemtap/tapset/*.stp', found 36
> Searched '/usr/local/share/systemtap/tapset/LKET/*.stp', found 19
> Pass 1: parsed user script and 56 library script(s) in 320usr/10sys/356real ms.
> control symbols: kts: 0x0 kte: 0x0 stext: 0x0

This is very curious.  those 3 control symbols shouldn't be 0: kts is 
'__kprobes_text_start', kte is '__kprobes_text_end', and stext is 
'_stext'.  Can you grep for those symbols in /proc/kallsyms and see if 
you find them?

If you can't find /proc/kallsyms, you need to build your kernel with 
CONFIG_KALLSYMS.  If you can find those symbols in /proc/kallsyms, I'd 
bet systemtap can't find your kernel's debuginfo.

Hope this helps.

--
David Smith
dsmith@redhat.com
Red Hat
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