Re: [PATCH] selftests/ftrace: check for do_sys_openat2 in user-memory test

[Colin Ian King <colin.king@canonical.com>]

On 02/10/2020 14:07, Masami Hiramatsu wrote:
> On Thu,  1 Oct 2020 09:56:41 +0100
> Colin King <colin.king@canonical.com> wrote:
> 
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> 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@canonical.com>
>> ---
>>  .../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.

Indeed, thanks. I'll send a V2 shortly.

> 
> Thank you!
>