If the user specifies a nonexistent field for a hist trigger, the current code correctly flags that as an error, but doesn't tell the user what happened. Fix this by invoking hist_err() with an appropriate message when nonexistent fields are specified. Before: # echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger -su: echo: write error: Invalid argument # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist After: # echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger -su: echo: write error: Invalid argument # cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist ERROR: Couldn't find field: pid Last command: keys=pid:ts0=common_timestamp.usecs Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx> Reported-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> --- kernel/trace/trace_events_hist.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 66c87be..f231fa2 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -2481,6 +2481,7 @@ static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data, else { field = trace_find_event_field(file->event_call, field_name); if (!field || !field->size) { + hist_err("Couldn't find field: ", field_name); field = ERR_PTR(-EINVAL); goto out; } -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html