On 28 Apr 2017 at 14:21, Frank Ch. Eigler wrote:
>
> Hi -
>
> > [...] Or perhaps I'm jusy lazy. Basically... these two tools need a
> > kernel "helper", need debugging symbol information (quite obviously,
> > to print function args) [...]
>
> Sorry about that, I'm spoiled with a distro that makes debuginfo
> really easy to find & install. :-) I should have listed this variant
> of the script instead. It doesn't need debuginfo (because stap
> developers have coded up a considerable heuristic database for
> syscalls).
>
> # stap -e '
> probe nd_syscall.{adjtimex,clock_adjtime,clock_settime}
> { println(tid(), " ", ppfunc()," ",argstr) }
> probe nd_syscall.{adjtimex,clock_adjtime,clock_settime}.return
> { println(tid(), " ", ppfunc()," ",retstr) }
> '
>
Dear Mr. Eigler,
thanks a lot for your super-swift responses :-)
and thanks for this particular tip.
Good to know about this for the future, but at the moment in my
Debian I'm stuck at some other problem. This is what I get:
stap: Symbol `SSL_ImplementedCiphers' has different size in shared
object, consider re-linking
ERROR: module version mismatch (#1 SMP Debian 3.16.39-1+deb8u2
(2017-03-07) vs #1 SMP Debian 3.16.7-ckt11-1+deb8u3 (2015-08-04)),
release 3.16.0-4-amd64
WARNING: /usr/bin/staprun exited with status: 1
The absence of "debugging grade" symbol tables doesn't seem to be a
problem.
If I read this correctly, the tracer module (something.ko) that comes
packaged in the debianese "systemtap" package is a different version
than the running default kernel, so it doesn't load. This is after
apt-get update && apt-get upgrade.
Also, your examples with multiple syscalls in.{curly,braces} are
probably too modern syntax for the old systemtap packaged in Debian
(but if I expand them by hand, the parser works fine.)
I could follow up, maybe roll my own kernel, get a fresh upstream
version of systemtap and recompile from source, resolve any
dependencies, and once it compiles, I would be able to run your
examples...
again, at the moment I'm too lazy for that. Not motivated enough.
I still very much appreciate your instructions :-)
It's good to know that these marvellous things are possible.
Frank Rysanek
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