Commit 9236eebd authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (Google)
Browse files

tracing: Fix fully-qualified variable reference printing in histograms 

The syntax for fully-qualified variable references in histograms is
subsys.event.$var, which is parsed correctly, but not displayed correctly
when printing a histogram spec. The current code puts the $ reference at
the beginning of the fully-qualified variable name i.e. $subsys.event.var,
which is incorrect.

Before:

trigger info: hist:keys=next_comm:vals=hitcount:wakeup_lat=common_timestamp.usecs-$sched.sched_wakeup.ts0: ...

After:

trigger info: hist:keys=next_comm:vals=hitcount:wakeup_lat=common_timestamp.usecs-sched.sched_wakeup.$ts0: ...

Link: https://patch.msgid.link/5dee9a86d062a4dd68c2214f3d90ac93811e1951.1776112478.git.zanussi@kernel.org


Signed-off-by: default avatarTom Zanussi <zanussi@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent fad217e1

kernel/trace/trace_events_hist.c

+10 −5
Original line number Diff line number Diff line
@@ -1361,9 +1361,12 @@ static const char *hist_field_name(struct hist_field *field, 
		 field->flags & HIST_FIELD_FL_VAR_REF) {

		if (field->system) {

			static char full_name[MAX_FILTER_STR_VAL];

			static char *fmt;

			int len;



			len = snprintf(full_name, sizeof(full_name), "%s.%s.%s",

			fmt = field->flags & HIST_FIELD_FL_VAR_REF ? "%s.%s.$%s" : "%s.%s.%s";



			len = snprintf(full_name, sizeof(full_name), fmt,

				       field->system, field->event_name,

				       field->name);

			if (len >= sizeof(full_name))
@@ -1742,9 +1745,10 @@ static const char *get_hist_field_flags(struct hist_field *hist_field) 


static void expr_field_str(struct hist_field *field, char *expr)

{

	if (field->flags & HIST_FIELD_FL_VAR_REF)

	if (field->flags & HIST_FIELD_FL_VAR_REF) {

		if (!field->system)

			strcat(expr, "$");

	else if (field->flags & HIST_FIELD_FL_CONST) {

	} else if (field->flags & HIST_FIELD_FL_CONST) {

		char str[HIST_CONST_DIGITS_MAX];



		snprintf(str, HIST_CONST_DIGITS_MAX, "%llu", field->constant);
@@ -6156,6 +6160,7 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) 
	else if (field_name) {

		if (hist_field->flags & HIST_FIELD_FL_VAR_REF ||

		    hist_field->flags & HIST_FIELD_FL_ALIAS)

			if (!hist_field->system)

				seq_putc(m, '$');

		seq_printf(m, "%s", field_name);

	} else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)