2020-05-20 07:42:53

by Jiri Olsa

Subject: [PATCH] perf stat: Fail on extra comma while parsing events

Ian reported that we allow to parse following:

$ perf stat -e ,cycles true

which is wrong and we should fail, like we do with this fix:

$ perf stat -e ,cycles true
event syntax error: ',cycles'
\___ parser error

The reason is that we don't have rule for ',' in 'event'
start condition and it's matched and accepted by default
rule.

Adding scanner debug support (that Ian already added for
expr code), which was really useful for finding this. It's
enabled together with bison debug via 'make PARSER_DEBUG=1'.

Reported-by: Ian Rogers <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
---
tools/perf/util/parse-events.c | 1 +
tools/perf/util/parse-events.l | 4 +++-
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index e37a6a3e6217..d251c8a778b8 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -2014,6 +2014,7 @@ static int parse_events__scanner(const char *str, void *parse_state, int start_t

#ifdef PARSER_DEBUG
parse_events_debug = 1;
+ parse_events_set_debug(1, scanner);
#endif
ret = parse_events_parse(parse_state, scanner);

diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index c589fc42f058..394132254447 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -252,7 +252,9 @@ modifier_bp [rwx]{1,3}
BEGIN(INITIAL);
REWIND(0);
}
-
+, {
+ return ',';
+ }
}

<array>{
--
2.25.4

2020-05-20 07:55:34

by Ian Rogers

Subject: Re: [PATCH] perf stat: Fail on extra comma while parsing events

On Wed, May 20, 2020 at 12:41 AM Jiri Olsa <[email protected]> wrote:
>
> Ian reported that we allow to parse following:
>
> $ perf stat -e ,cycles true
>
> which is wrong and we should fail, like we do with this fix:
>
> $ perf stat -e ,cycles true
> event syntax error: ',cycles'
> \___ parser error
>
> The reason is that we don't have rule for ',' in 'event'
> start condition and it's matched and accepted by default
> rule.
>
> Adding scanner debug support (that Ian already added for
> expr code), which was really useful for finding this. It's
> enabled together with bison debug via 'make PARSER_DEBUG=1'.
>
> Reported-by: Ian Rogers <[email protected]>
> Signed-off-by: Jiri Olsa <[email protected]>

Acked-by: Ian Rogers <[email protected]>

Thanks!
Ian

Ian

> ---
> tools/perf/util/parse-events.c | 1 +
> tools/perf/util/parse-events.l | 4 +++-
> 2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index e37a6a3e6217..d251c8a778b8 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -2014,6 +2014,7 @@ static int parse_events__scanner(const char *str, void *parse_state, int start_t
>
> #ifdef PARSER_DEBUG
> parse_events_debug = 1;
> + parse_events_set_debug(1, scanner);
> #endif
> ret = parse_events_parse(parse_state, scanner);
>
> diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> index c589fc42f058..394132254447 100644
> --- a/tools/perf/util/parse-events.l
> +++ b/tools/perf/util/parse-events.l
> @@ -252,7 +252,9 @@ modifier_bp [rwx]{1,3}
> BEGIN(INITIAL);
> REWIND(0);
> }
> -
> +, {
> + return ',';
> + }
> }
>
> <array>{
> --
> 2.25.4
>

2020-05-20 13:34:51

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] perf stat: Fail on extra comma while parsing events

Em Wed, May 20, 2020 at 12:51:24AM -0700, Ian Rogers escreveu:
> On Wed, May 20, 2020 at 12:41 AM Jiri Olsa <[email protected]> wrote:
> >
> > Ian reported that we allow to parse following:
> >
> > $ perf stat -e ,cycles true
> >
> > which is wrong and we should fail, like we do with this fix:
> >
> > $ perf stat -e ,cycles true
> > event syntax error: ',cycles'
> > \___ parser error
> >
> > The reason is that we don't have rule for ',' in 'event'
> > start condition and it's matched and accepted by default
> > rule.
> >
> > Adding scanner debug support (that Ian already added for
> > expr code), which was really useful for finding this. It's
> > enabled together with bison debug via 'make PARSER_DEBUG=1'.
> >
> > Reported-by: Ian Rogers <[email protected]>
> > Signed-off-by: Jiri Olsa <[email protected]>
>
> Acked-by: Ian Rogers <[email protected]>

Thanks, applied.

- Arnaldo