From: Tom Zanussi If the user specifies an invalid field modifier 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 invalid modifiers are specified. Before: # echo 'hist:keys=pid:ts0=common_timestamp.junkusecs' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger -su: echo: write error: Invalid argument # cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist After: # echo 'hist:keys=pid:ts0=common_timestamp.junkusecs' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger -su: echo: write error: Invalid argument # cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist ERROR: Invalid field modifier: junkusecs Last command: keys=pid:ts0=common_timestamp.junkusecs Link: http://lkml.kernel.org/r/b043c59fa79acd06a5f14a1d44dee9e5a3cd1248.1524790601.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) --- 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 f231fa2a3dcd..b9061ed59bbd 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -2466,6 +2466,7 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, else if (strcmp(modifier, "usecs") == 0) *flags |= HIST_FIELD_FL_TIMESTAMP_USECS; else { + hist_err("Invalid field modifier: ", modifier); field = ERR_PTR(-EINVAL); goto out; } -- 2.17.0