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Commit 5ec432d7 authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (VMware)
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tracing: Add field parsing hist error for hist triggers 

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

Link: http://lkml.kernel.org/r/fdc8746969d16906120f162b99dd71c741e0b62c.1524790601.git.tom.zanussi@linux.intel.com



Signed-off-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Reported-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 608940da

kernel/trace/trace_events_hist.c

+1 −0
Original line number Diff line number Diff line
@@ -2481,6 +2481,7 @@ parse_field(struct hist_trigger_data *hist_data, struct trace_event_file *file, 
	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;

		}