Merge tag 'perf-tools-fixes-for-v6.7-2-2023-12-08' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

Pull perf tools fixes from Namhyung Kim:
 "A random set of small bug fixes including:

   - Fix segfault on AmpereOne due to missing default metricgroup name

   - Fix segfault on `perf list --json` due to NULL pointer"

* tag 'perf-tools-fixes-for-v6.7-2-2023-12-08' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools:
  perf list: Fix JSON segfault by setting the used skip_duplicate_pmus callback
  perf vendor events arm64: AmpereOne: Add missing DefaultMetricgroupName fields
  perf metrics: Avoid segv if default metricgroup isn't set

Author: torvalds

tools/perf/builtin-list.c

@@ -434,6 +434,11 @@ static void json_print_metric(void *ps __maybe_unused, const char *group,
 	strbuf_release(&buf);
 }
 
+static bool json_skip_duplicate_pmus(void *ps __maybe_unused)
+{
+	return false;
+}
+
 static bool default_skip_duplicate_pmus(void *ps)
 {
 	struct print_state *print_state = ps;
@@ -503,6 +508,7 @@ int cmd_list(int argc, const char **argv)
 			.print_end = json_print_end,
 			.print_event = json_print_event,
 			.print_metric = json_print_metric,
+			.skip_duplicate_pmus = json_skip_duplicate_pmus,
 		};
 		ps = &json_ps;
 	} else {

tools/perf/pmu-events/arch/arm64/ampere/ampereone/metrics.json

@@ -231,13 +231,15 @@
         "MetricName": "slots_lost_misspeculation_fraction",
         "MetricExpr": "100 * ((OP_SPEC - OP_RETIRED) / (CPU_CYCLES * #slots))",
         "BriefDescription": "Fraction of slots lost due to misspeculation",
+        "DefaultMetricgroupName": "TopdownL1",
         "MetricGroup": "Default;TopdownL1",
         "ScaleUnit": "1percent of slots"
     },
     {
         "MetricName": "retired_fraction",
         "MetricExpr": "100 * (OP_RETIRED / (CPU_CYCLES * #slots))",
         "BriefDescription": "Fraction of slots retiring, useful work",
+        "DefaultMetricgroupName": "TopdownL1",
         "MetricGroup": "Default;TopdownL1",
 	"ScaleUnit": "1percent of slots"
     },

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);