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Date: Mon, 30 Mar 2015 19:46:55 +0200
From: Jiri Olsa <jolsa@redhat.com>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
        Arnaldo Carvalho de Melo <acme@infradead.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        David Ahern <dsahern@gmail.com>, linux-kernel@vger.kernel.org,
        Martin Cermak <mcermak@redhat.com>
Subject: [RFC] perf probe: -x option position issue
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hi,
Martin found out following issue.. having following ex binary:

---
int main(void)
{
        return 0;
}
---

following will create uprobe on main:

  [root@dell-per510-01 perf]# gcc -g -o ex ex.c
  [root@dell-per510-01 perf]# ./perf probe -x ./ex -a main
  Added new event:
    probe_ex:main        (on main in /root/linux/tools/perf/ex)

  You can now use it in all perf tools, such as:

          perf record -e probe_ex:main -aR sleep 1

  [root@dell-per510-01 perf]# cat /sys/kernel/debug/tracing/uprobe_events 
  p:probe_ex/main /root/linux/tools/perf/ex:0x00000000000004f6


while following will create (?) kprobe with complain in dmesg:

  [root@dell-per510-01 perf]# gcc -g -o ex ex.c
  [root@dell-per510-01 perf]# ./perf probe -a main -x ./ex
  Added new event:
    probe:main           (on main in ex)

  You can now use it in all perf tools, such as:

          perf record -e probe:main -aR sleep 1

  [root@dell-per510-01 perf]# dmesg | tail -2
  [16986.182159] Could not insert probe at ex:main+0: -2
  [16986.187030] This probe might be able to register aftertarget module is loaded. Continue.


that does not seem as an expected behaviour, or am I missing something?

thanks,
jirka