Steven Rostedt <rostedt@xxxxxxxxxxx> writes:
> On Mon, 29 Nov 2021 11:13:31 +0100
> Sven Schnelle <svens@xxxxxxxxxxxxx> wrote:
>
>
>> This breaks the trigger-field-variable-support.tc from the ftrace test
>> suite at least on s390:
>>
>> echo
>> 'hist:keys=next_comm:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,sched.sched_waking.prio,next_comm)
>> if next_comm=="ping"'
>> linux/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc: line 15: echo: write error: Invalid argument
>>
>> I added a debugging line into check_synth_field():
>>
>> [ 44.091037] field->size 16, hist_field->size 16, field->is_signed 1, hist_field->is_signed 0
>>
>> Note the difference in the signed field.
>
> That should not break on strings.
>
> Does this fix it (if you keep the patch)?
It does. Thanks!
> -- Steve
>
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 9555b8e1d1e3..319f9c8ca7e7 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -3757,7 +3757,7 @@ static int check_synth_field(struct synth_event *event,
>
> if (strcmp(field->type, hist_field->type) != 0) {
> if (field->size != hist_field->size ||
> - field->is_signed != hist_field->is_signed)
> + (!field->is_string && field->is_signed != hist_field->is_signed))
> return -EINVAL;
> }
>
