Re: [BUG] perf probe can't insert return kprobe

Jiri Olsa
2015-01-09T15:31:08Z

On Sat, Jan 10, 2015 at 12:21:13AM +0900, Namhyung Kim wrote:
> On Fri, Jan 09, 2015 at 03:55:39PM +0100, Jiri Olsa wrote:
> > hi,
> > I couldn't use following perf command to insert return probe:
> >
> > # perf probe -a fork_exit=do_fork%return
> > Added new event:
> > Failed to write event: Invalid argument
> > Error: Failed to add events.
> >
> >
> > I'm pretty sure I used this command before, so seems like
> > it's broken. I can still use debugfs tracing interface to
> > do that:
> > # echo 'r:do_fork_entry do_fork' > kprobe_events
> >
> > I used Arnaldo's latest perf/core and FC20 kernel:
> >
> > # uname -a
> > Linux krava 3.17.7-200.fc20.x86_64 #1 SMP Wed Dec 17 03:35:33 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
> > # ./perf version
> > perf version 3.18.g6a7d78
> >
>
> Is it just return probe? Did it work for normal kprobes?

yep, works for normal probes

> Maybe it's related to the below:
>
> https://lkml.org/lkml/2014/12/31/15
>
> Have you check the acme/perf/urgent too?

hum.. can't access lkml, I'll check, also with perf/urgent

thanks,
jirka