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Re: "No match for probe point" for syscall.open with tutorial example strace-open.stp
- From: Fredy Neeser <Fredy dot Neeser at solnet dot ch>
- To: David Smith <dsmith at redhat dot com>
- Cc: systemtap at sources dot redhat dot com
- Date: Thu, 23 Aug 2007 23:45:45 +0200
- Subject: Re: "No match for probe point" for syscall.open with tutorial example strace-open.stp
- References: <loom.20070823T214142-222@post.gmane.org> <46CDF870.9080907@redhat.com>
David Smith schrieb:
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.
Thanks for your thoughts. The kernel is configured with
CONFIG_KALLSYMS=y
# CONFIG_KALLSYMS_ALL is not set
CONFIG_KALLSYMS_EXTRA_PASS=y
The symbols are there:
[fn@mythen ~]$ cat /proc/kallsyms | grep __kprobes_text_start
c02edf20 T __kprobes_text_start
[fn@mythen ~]$ cat /proc/kallsyms | grep __kprobes_text_end
c02efb87 T __kprobes_text_end
[fn@mythen ~]$ cat /proc/kallsyms | grep _stext
c0100294 T _stext
Hmm ... I will also try on another machine.
Cheers,
Fredy.