diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 7bd61028327b..87a1f4cf8760 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -3215,7 +3215,9 @@ static int perf_timehist__process_sample(const struct perf_tool *tool,
 		.cpu = sample->cpu,
 	};
 
-	if (this_cpu.cpu > sched->max_cpu.cpu)
+	/* max_cpu indexes arrays allocated with MAX_CPUS entries */
+	if (this_cpu.cpu >= 0 && this_cpu.cpu < MAX_CPUS &&
+	    this_cpu.cpu > sched->max_cpu.cpu)
 		sched->max_cpu = this_cpu;
 
 	if (evsel->handler != NULL) {
@@ -3385,8 +3387,8 @@ static int perf_sched__timehist(struct perf_sched *sched)
 		perf_session__set_tracepoints_handlers(session, migrate_handlers))
 		goto out;
 
-	/* pre-allocate struct for per-CPU idle stats */
-	sched->max_cpu.cpu = env->nr_cpus_online;
+	/* pre-allocate struct for per-CPU idle stats; cap to array bounds */
+	sched->max_cpu.cpu = min(env->nr_cpus_online, MAX_CPUS);
 	if (sched->max_cpu.cpu == 0)
 		sched->max_cpu.cpu = 4;
 	if (init_idle_threads(sched->max_cpu.cpu))