Re: [PATCH v1] perf metrics: Avoid segv with --topdown

["Liang, Kan" <kan.liang@linux.intel.com>]

On 2023-05-15 6:45 p.m., Ian Rogers wrote:
> Some metrics may not have a metric_group which can result in segvs
> with "perf stat --topdown". Add a condition for the no metric_group
> case.
> 
> Fixes: 1647cd5b8802 ("perf stat: Implement --topdown using json metrics")
> Reported-by: Kan Liang <kan.liang@linux.intel.com>
> Signed-off-by: Ian Rogers <irogers@google.com>

Tested-by: Kan Liang <kan.liang@linux.intel.com>

Thanks,
Kan

> ---
>  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 4e7d41d285b4..5e9c657dd3f7 100644
> --- a/tools/perf/util/metricgroup.c
> +++ b/tools/perf/util/metricgroup.c
> @@ -1672,7 +1672,7 @@ static int metricgroup__topdown_max_level_callback(const struct pmu_metric *pm,
>  {
>  	unsigned int *max_level = data;
>  	unsigned int level;
> -	const char *p = strstr(pm->metric_group, "TopdownL");
> +	const char *p = strstr(pm->metric_group ?: "", "TopdownL");
>  
>  	if (!p || p[8] == '\0')
>  		return 0;