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

[Arnaldo Carvalho de Melo <acme@redhat.com>]

Em Fri, Jan 09, 2015 at 03:55:39PM +0100, Jiri Olsa escreveu:
> 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.

Wonder if we have any way of forcing 'perf probe' to show what it will
feed the kernel, perhaps -v?

> 
> 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
> 
> 
> thanks,
> jirka