[PATCH v1 1/2] perf metrics: Avoid segv if default metricgroup isn't set

[Ilkka Koskinen]

On Mon, 4 Dec 2023, Ian Rogers wrote:
> A metric is default by having "Default" within its groups. The default
> metricgroup name needn't be set and this can result in segv in
> default_metricgroup_cmp and perf_stat__print_shadow_stats_metricgroup
> that assume it has a value when there is a Default metric group. To
> avoid the segv initialize the value to "".
>
> Fixes: 1c0e47956a8e ("perf metrics: Sort the Default metricgroup")
> Signed-off-by: Ian Rogers <irogers at google.com>

Thanks! I was going to look for the bug but got pulled to other 
tasks. The patch looks good to me and I tested it successfully on 
AmpereOne.

   Reviewed-and-tested-by: Ilkka Koskinen <ilkka at os.amperecomputing.com>


Cheers, Ilkka

> ---
> tools/perf/util/metricgroup.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
> index 0484736d9fe4..ca3e0404f187 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -225,7 +225,7 @@ static struct metric *metric__new(const struct pmu_metric *pm,
>
> 	m->pmu = pm->pmu ?: "cpu";
> 	m->metric_name = pm->metric_name;
> -	m->default_metricgroup_name = pm->default_metricgroup_name;
> +	m->default_metricgroup_name = pm->default_metricgroup_name ?: "";
> 	m->modifier = NULL;
> 	if (modifier) {
> 		m->modifier = strdup(modifier);
> -- 
> 2.43.0.rc2.451.g8631bc7472-goog
>
>