From aa274f98b269b2babf37b6308f8a1a009ca4fc41 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 21 Oct 2021 13:41:31 +0200 Subject: [PATCH] selftests/bpf: Fix possible/online index mismatch in perf_buffer test The perf_buffer fails on system with offline cpus: # test_progs -t perf_buffer serial_test_perf_buffer:PASS:nr_cpus 0 nsec serial_test_perf_buffer:PASS:nr_on_cpus 0 nsec serial_test_perf_buffer:PASS:skel_load 0 nsec serial_test_perf_buffer:PASS:attach_kprobe 0 nsec serial_test_perf_buffer:PASS:perf_buf__new 0 nsec serial_test_perf_buffer:PASS:epoll_fd 0 nsec skipping offline CPU #4 serial_test_perf_buffer:PASS:perf_buffer__poll 0 nsec serial_test_perf_buffer:PASS:seen_cpu_cnt 0 nsec serial_test_perf_buffer:PASS:buf_cnt 0 nsec ... serial_test_perf_buffer:PASS:fd_check 0 nsec serial_test_perf_buffer:PASS:drain_buf 0 nsec serial_test_perf_buffer:PASS:consume_buf 0 nsec serial_test_perf_buffer:FAIL:cpu_seen cpu 5 not seen #88 perf_buffer:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED If the offline cpu is from the middle of the possible set, we get mismatch with possible and online cpu buffers. The perf buffer test calls perf_buffer__consume_buffer for all 'possible' cpus, but the library holds only 'online' cpu buffers and perf_buffer__consume_buffer returns them based on index. Adding extra (online) index to keep track of online buffers, we need the original (possible) index to trigger trace on proper cpu. Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20211021114132.8196-3-jolsa@kernel.org --- tools/testing/selftests/bpf/prog_tests/perf_buffer.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/perf_buffer.c b/tools/testing/selftests/bpf/prog_tests/perf_buffer.c index 877600392851..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; @@ -111,15 +111,15 @@ void serial_test_perf_buffer(void) "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: -- 2.11.0