Re: [PATCH 2/2] perf parse-events: Avoid an uninitialized read.

[Jiri Olsa <jolsa@redhat.com>]

On Tue, Aug 25, 2020 at 09:29:10PM -0700, Ian Rogers wrote:
> With a fake_pmu the pmu_info isn't populated by perf_pmu__check_alias.
> In this case, don't try to copy the uninitialized values to the evsel.
> 
> Signed-off-by: Ian Rogers <irogers@google.com>

Acked-by: Jiri Olsa <jolsa@redhat.com>

thanks,
jirka

> ---
>  tools/perf/util/parse-events.c | 30 +++++++++++++++++-------------
>  1 file changed, 17 insertions(+), 13 deletions(-)
> 
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index 9f7260e69113..3d7a48b488ed 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -1533,19 +1533,23 @@ int parse_events_add_pmu(struct parse_events_state *parse_state,
>  	evsel = __add_event(list, &parse_state->idx, &attr, true,
>  			    get_config_name(head_config), pmu,
>  			    &config_terms, auto_merge_stats, NULL);
> -	if (evsel) {
> -		evsel->unit = info.unit;
> -		evsel->scale = info.scale;
> -		evsel->per_pkg = info.per_pkg;
> -		evsel->snapshot = info.snapshot;
> -		evsel->metric_expr = info.metric_expr;
> -		evsel->metric_name = info.metric_name;
> -		evsel->pmu_name = name ? strdup(name) : NULL;
> -		evsel->use_uncore_alias = use_uncore_alias;
> -		evsel->percore = config_term_percore(&evsel->config_terms);
> -	}
> -
> -	return evsel ? 0 : -ENOMEM;
> +	if (!evsel)
> +		return -ENOMEM;
> +
> +	evsel->pmu_name = name ? strdup(name) : NULL;
> +	evsel->use_uncore_alias = use_uncore_alias;
> +	evsel->percore = config_term_percore(&evsel->config_terms);
> +
> +	if (parse_state->fake_pmu)
> +		return 0;
> +
> +	evsel->unit = info.unit;
> +	evsel->scale = info.scale;
> +	evsel->per_pkg = info.per_pkg;
> +	evsel->snapshot = info.snapshot;
> +	evsel->metric_expr = info.metric_expr;
> +	evsel->metric_name = info.metric_name;
> +	return 0;
>  }
>  
>  int parse_events_multi_pmu_add(struct parse_events_state *parse_state,
> -- 
> 2.28.0.297.g1956fa8f8d-goog
>