1 files changed, 57 insertions, 23 deletions

diff --git a/tools/perf/util/bpf_counter_cgroup.c b/tools/perf/util/bpf_counter_cgroup.c
index 690be3ce3e11..17d7196c6589 100644
--- a/tools/perf/util/bpf_counter_cgroup.c
+++ b/tools/perf/util/bpf_counter_cgroup.c
@@ -4,6 +4,7 @@
 /* Copyright (c) 2021 Google */
 
 #include <assert.h>
+#include <errno.h>
 #include <limits.h>
 #include <unistd.h>
 #include <sys/file.h>
@@ -27,6 +28,7 @@
 #include "cpumap.h"
 #include "thread_map.h"
 
+#include "bpf_skel/bperf_cgroup.h"
 #include "bpf_skel/bperf_cgroup.skel.h"
 
 static struct perf_event_attr cgrp_switch_attr = {
@@ -42,6 +44,55 @@ static struct bperf_cgroup_bpf *skel;
 
 #define FD(evt, cpu) (*(int *)xyarray__entry(evt->core.fd, cpu, 0))
 
+static void setup_rodata(struct bperf_cgroup_bpf *sk, int evlist_size)
+{
+	int map_size, total_cpus = cpu__max_cpu().cpu;
+
+	sk->rodata->num_cpus = total_cpus;
+	sk->rodata->num_events = evlist_size / nr_cgroups;
+
+	if (cgroup_is_v2("perf_event") > 0)
+		sk->rodata->use_cgroup_v2 = 1;
+
+	BUG_ON(evlist_size % nr_cgroups != 0);
+
+	/* we need one copy of events per cpu for reading */
+	map_size = total_cpus * evlist_size / nr_cgroups;
+	bpf_map__set_max_entries(sk->maps.events, map_size);
+	bpf_map__set_max_entries(sk->maps.cgrp_idx, nr_cgroups);
+	/* previous result is saved in a per-cpu array */
+	map_size = evlist_size / nr_cgroups;
+	bpf_map__set_max_entries(sk->maps.prev_readings, map_size);
+	/* cgroup result needs all events (per-cpu) */
+	map_size = evlist_size;
+	bpf_map__set_max_entries(sk->maps.cgrp_readings, map_size);
+}
+
+static void test_max_events_program_load(void)
+{
+#ifndef NDEBUG
+	/*
+	 * Test that the program verifies with the maximum number of events. If
+	 * this test fails unfortunately perf needs recompiling with a lower
+	 * BPERF_CGROUP__MAX_EVENTS to avoid BPF verifier issues.
+	 */
+	int err, max_events = BPERF_CGROUP__MAX_EVENTS * nr_cgroups;
+	struct bperf_cgroup_bpf *test_skel = bperf_cgroup_bpf__open();
+
+	if (!test_skel) {
+		pr_err("Failed to open cgroup skeleton\n");
+		return;
+	}
+	setup_rodata(test_skel, max_events);
+	err = bperf_cgroup_bpf__load(test_skel);
+	if (err) {
+		pr_err("Failed to load cgroup skeleton with max events %d.\n",
+			BPERF_CGROUP__MAX_EVENTS);
+	}
+	bperf_cgroup_bpf__destroy(test_skel);
+#endif
+}
+
 static int bperf_load_program(struct evlist *evlist)
 {
 	struct bpf_link *link;
@@ -50,35 +101,18 @@ static int bperf_load_program(struct evlist *evlist)
 	int i, j;
 	struct perf_cpu cpu;
 	int total_cpus = cpu__max_cpu().cpu;
-	int map_size, map_fd;
-	int prog_fd, err;
+	int map_fd, prog_fd, err;
+
+	set_max_rlimit();
+
+	test_max_events_program_load();
 
 	skel = bperf_cgroup_bpf__open();
 	if (!skel) {
 		pr_err("Failed to open cgroup skeleton\n");
 		return -1;
 	}
-
-	skel->rodata->num_cpus = total_cpus;
-	skel->rodata->num_events = evlist->core.nr_entries / nr_cgroups;
-
-	if (cgroup_is_v2("perf_event") > 0)
-		skel->rodata->use_cgroup_v2 = 1;
-
-	BUG_ON(evlist->core.nr_entries % nr_cgroups != 0);
-
-	/* we need one copy of events per cpu for reading */
-	map_size = total_cpus * evlist->core.nr_entries / nr_cgroups;
-	bpf_map__set_max_entries(skel->maps.events, map_size);
-	bpf_map__set_max_entries(skel->maps.cgrp_idx, nr_cgroups);
-	/* previous result is saved in a per-cpu array */
-	map_size = evlist->core.nr_entries / nr_cgroups;
-	bpf_map__set_max_entries(skel->maps.prev_readings, map_size);
-	/* cgroup result needs all events (per-cpu) */
-	map_size = evlist->core.nr_entries;
-	bpf_map__set_max_entries(skel->maps.cgrp_readings, map_size);
-
-	set_max_rlimit();
+	setup_rodata(skel, evlist->core.nr_entries);
 
 	err = bperf_cgroup_bpf__load(skel);
 	if (err) {