From: fche@redhat.com (Frank Ch. Eigler)
To: "Klein, Matt" <mklein@amazon.com>
Cc: "systemtap@sourceware.org" <systemtap@sourceware.org>
Subject: Re: Issues with probing multiple modules in script
Date: Sat, 31 Dec 2011 01:33:00 -0000 [thread overview]
Message-ID: <y0mr4zo62un.fsf@fche.csb> (raw)
In-Reply-To: <FCDCC4AE6C28B44B90993D9894683575B35B07D5@EX-SEA3-A.ant.amazon.com> (Matt Klein's message of "Tue, 27 Dec 2011 14:06:14 -0800")
Hi -
mklein wrote:
> SystemTap translator/driver (version 1.3/0.152 non-git sources)
That's a little old, but probably not a factor.
> If I try to probe a single module, everything works as
> expected. However if I probe multiple modules, it seems like probes
> in the first module found works fine, but any probes on subsequent
> modules don't actually work. I also see the following error for all
> modules other than the first:
> WARNING: missing unwind/symbol data for module ...
This message indicates only that operations such as symname() /
backtrace() might not be able to cover those other modules. (This
information is extracted during pass 3, in translate.cxx
dump_unwindsyms().) There may be a bug here, but I couldn't reproduce
the problem here. Could you share the "stap --vp 009 -p4 ..." output?
The probes' basic activity should be otherwise unaffected, meaning
that you should be able to place probes whereever.
> I have looked through the -vvvvv output, and it looks to me like all
> of the module probe points are being identified correctly, but then
> I see the WARNING message and it doesn't look like the probes ever
> actually get invoked.
Why do you think they're not getting invoked? You can try "stap -t
..." to get hit counts/times for individual probe points. You could
try "stap -DDEBUG_SYMBOLS ..." to see some of the runtime
symbol-lookup-related activity.
> Is there anything obvious I am doing wrong (like probing multiple
> modules from the same script doesn't work)? [...]
It should all work smoothly. We just need more information to figure
out what's going wrong.
- FChE
prev parent reply other threads:[~2011-12-28 17:08 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-28 8:07 Klein, Matt
2011-12-31 1:33 ` Frank Ch. Eigler [this message]
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