On Thu, 1 Oct 2020 09:56:41 +0100
Colin King <colin.king@xxxxxxxxxxxxx> wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> More recent libc implementations are now using openat/openat2 system
> calls so also add do_sys_openat2 to the tracing so that the test
> passes on these systems because do_sys_open may not be called.
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> .../testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc
> index a30a9c07290d..cf1b4c3e9e6b 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_user.tc
> @@ -9,6 +9,8 @@ grep -A10 "fetcharg:" README | grep -q '\[u\]<offset>' || exit_unsupported
> :;: "user-memory access syntax and ustring working on user memory";:
> echo 'p:myevent do_sys_open path=+0($arg2):ustring path2=+u0($arg2):string' \
> > kprobe_events
OK, at first, you need to check the kernel has do_sys_openat2 from
/proc/kallsyms (grep -qw will help you), because it is new syscall.
> +echo 'p:myevent2 do_sys_openat2 path=+0($arg2):ustring path2=+u0($arg2):string' \
> + > kprobe_events
Also, you need to append (">>") it instead overwrite (">") to kprobe_events.
>
> grep myevent kprobe_events | \
> grep -q 'path=+0($arg2):ustring path2=+u0($arg2):string'
And also you have to enable both myevent and myevent2 (if exists) after
this.
Then I think your patch will work correctly.
Thank you!
--
Masami Hiramatsu <mhiramat@xxxxxxxxxx>
