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Message-Id: <fdc8746969d16906120f162b99dd71c741e0b62c.1524790601.git.tom.zanussi@linux.intel.com>
Date: Thu, 26 Apr 2018 20:04:48 -0500
From: Tom Zanussi <tom.zanussi@...ux.intel.com>
To: rostedt@...dmis.org
Cc: tglx@...utronix.de, mhiramat@...nel.org, namhyung@...nel.org,
vedang.patel@...el.com, bigeasy@...utronix.de,
joel.opensrc@...il.com, joelaf@...gle.com,
mathieu.desnoyers@...icios.com, baohong.liu@...el.com,
rajvi.jingar@...el.com, julia@...com, fengguang.wu@...el.com,
linux-kernel@...r.kernel.org, linux-rt-users@...r.kernel.org,
Tom Zanussi <tom.zanussi@...ux.intel.com>
Subject: [PATCH 2/3] 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
Signed-off-by: Tom Zanussi <tom.zanussi@...ux.intel.com>
Reported-by: Masami Hiramatsu <mhiramat@...nel.org>
---
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
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