Re: [PATCH] perf tools: Fix parser for empty pmu terms case

From: Jiri Olsa
Date: Mon May 07 2018 - 04:12:18 EST


On Mon, May 07, 2018 at 10:21:42AM +0300, Adrian Hunter wrote:
> On 06/05/18 17:28, Jiri Olsa wrote:
> > On Sat, May 05, 2018 at 08:43:11PM -0700, Andi Kleen wrote:
> >> Jiri Olsa <jolsa@xxxxxxxxxx> writes:
> >>
> >> Please fix this quickly, PT is currently totally non functional in Linus
> >> mainline.
> >
> > attached.. Kan, could you please test it wrt your latest changes?
> >
> > thanks,
> > jirka
> >
> >
> > ---
> > Adrian reported broken event parsing for Intel PT:
> >
> > $ perf record -e intel_pt//u uname
> > event syntax error: 'intel_pt//u'
> > \___ parser error
> > Run 'perf list' for a list of valid events
> >
> > It's caused by recent change in parsing grammar
> > (see Fixes: for commit).
> >
> > Adding special rule with empty terms config to handle
> > the reported case and moving the common rule code into
> > new parse_events_pmu function.
>
> Hi
>
> Can you explain why that is needed instead of just changing the grammar e.g.

well, for one, mine is working ;-)

[jolsa@krava perf]$ sudo ./perf record -e intel_pt//u uname
event syntax error: 'intel_pt//u'
\___ parser error
Run 'perf list' for a list of valid events

Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]

-e, --event <event> event selector. use 'perf list' to list available events


but yep, it's better solution.. with extra changes like below

jirka


---
diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 47f6399a309a..155d2570274f 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -73,6 +73,7 @@ static void inc_group_count(struct list_head *list,
%type <num> value_sym
%type <head> event_config
%type <head> opt_event_config
+%type <head> opt_pmu_config
%type <term> event_term
%type <head> event_pmu
%type <head> event_legacy_symbol
@@ -224,15 +225,15 @@ event_def: event_pmu |
event_bpf_file

event_pmu:
-PE_NAME '/' event_config '/'
+PE_NAME opt_pmu_config
{
struct list_head *list, *orig_terms, *terms;

- if (parse_events_copy_term_list($3, &orig_terms))
+ if (parse_events_copy_term_list($2, &orig_terms))
YYABORT;

ALLOC_LIST(list);
- if (parse_events_add_pmu(_parse_state, list, $1, $3, false, false)) {
+ if (parse_events_add_pmu(_parse_state, list, $1, $2, false, false)) {
struct perf_pmu *pmu = NULL;
int ok = 0;
char *pattern;
@@ -262,7 +263,7 @@ PE_NAME '/' event_config '/'
if (!ok)
YYABORT;
}
- parse_events_terms__delete($3);
+ parse_events_terms__delete($2);
parse_events_terms__delete(orig_terms);
$$ = list;
}
@@ -496,6 +497,17 @@ opt_event_config:
$$ = NULL;
}

+opt_pmu_config:
+'/' event_config '/'
+{
+ $$ = $2;
+}
+|
+'/' '/'
+{
+ $$ = NULL;
+}
+
start_terms: event_config
{
struct parse_events_state *parse_state = _parse_state;