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

From: Namhyung Kim
Date: Fri Jan 09 2015 - 10:21:27 EST


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?
Maybe it's related to the below:

https://lkml.org/lkml/2014/12/31/15

Have you check the acme/perf/urgent too?

Thanks,
Namhyung
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