diff --git a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c
index 6979aff4aab2..0b0cd045979b 100644
--- a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c
+++ b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c
@@ -45,7 +45,7 @@ int trigger_on_cpu(int cpu)
 
 void serial_test_perf_buffer(void)
 {
-	int err, on_len, nr_on_cpus = 0, nr_cpus, i;
+	int err, on_len, nr_on_cpus = 0, nr_cpus, i, j;
 	struct perf_buffer_opts pb_opts = {};
 	struct test_perf_buffer *skel;
 	cpu_set_t cpu_seen;
@@ -107,19 +107,19 @@ void serial_test_perf_buffer(void)
 		  "expect %d, seen %d\n", nr_on_cpus, CPU_COUNT(&cpu_seen)))
 		goto out_free_pb;
 
-	if (CHECK(perf_buffer__buffer_cnt(pb) != nr_cpus, "buf_cnt",
-		  "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_cpus))
+	if (CHECK(perf_buffer__buffer_cnt(pb) != nr_on_cpus, "buf_cnt",
+		  "got %zu, expected %d\n", perf_buffer__buffer_cnt(pb), nr_on_cpus))
 		goto out_close;
 
-	for (i = 0; i < nr_cpus; i++) {
+	for (i = 0, j = 0; i < nr_cpus; i++) {
 		if (i >= on_len || !online[i])
 			continue;
 
-		fd = perf_buffer__buffer_fd(pb, i);
+		fd = perf_buffer__buffer_fd(pb, j);
 		CHECK(fd < 0 || last_fd == fd, "fd_check", "last fd %d == fd %d\n", last_fd, fd);
 		last_fd = fd;
 
-		err = perf_buffer__consume_buffer(pb, i);
+		err = perf_buffer__consume_buffer(pb, j);
 		if (CHECK(err, "drain_buf", "cpu %d, err %d\n", i, err))
 			goto out_close;
 
@@ -127,12 +127,13 @@ void serial_test_perf_buffer(void)
 		if (trigger_on_cpu(i))
 			goto out_close;
 
-		err = perf_buffer__consume_buffer(pb, i);
-		if (CHECK(err, "consume_buf", "cpu %d, err %d\n", i, err))
+		err = perf_buffer__consume_buffer(pb, j);
+		if (CHECK(err, "consume_buf", "cpu %d, err %d\n", j, err))
 			goto out_close;
 
 		if (CHECK(!CPU_ISSET(i, &cpu_seen), "cpu_seen", "cpu %d not seen\n", i))
 			goto out_close;
+		j++;
 	}
 
 out_free_pb:
diff --git a/tools/testing/selftests/bpf/progs/test_perf_buffer.c b/tools/testing/selftests/bpf/progs/test_perf_buffer.c
index d37ce29fd393..a08874c5bdf2 100644
--- a/tools/testing/selftests/bpf/progs/test_perf_buffer.c
+++ b/tools/testing/selftests/bpf/progs/test_perf_buffer.c
@@ -12,7 +12,7 @@ struct {
 	__type(value, int);
 } perf_buf_map SEC(".maps");
 
-SEC("tp/raw_syscalls/sys_enter")
+SEC("tp/syscalls/sys_enter_nanosleep")
 int handle_sys_enter(void *ctx)
 {
 	int cpu = bpf_get_smp_processor_id();