From 3ced9b600234e6bb13cb25654ce44c4896485cf2 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Thu, 4 Jan 2018 13:55:04 -0800 Subject: tools/bpf: add a bpf selftest for stacktrace Added a bpf selftest in test_progs at tools directory for stacktrace. The test will populate a hashtable map and a stacktrace map at the same time with the same key, stackid. The user space will compare both maps, using BPF_MAP_LOOKUP_ELEM command and BPF_MAP_GET_NEXT_KEY command, to ensure that both have the same set of keys. Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/test_progs.c | 127 +++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) (limited to 'tools/testing/selftests/bpf/test_progs.c') diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index 09087ab..b549308 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -837,6 +837,132 @@ static void test_tp_attach_query(void) free(query); } +static int compare_map_keys(int map1_fd, int map2_fd) +{ + __u32 key, next_key; + char val_buf[PERF_MAX_STACK_DEPTH * sizeof(__u64)]; + int err; + + err = bpf_map_get_next_key(map1_fd, NULL, &key); + if (err) + return err; + err = bpf_map_lookup_elem(map2_fd, &key, val_buf); + if (err) + return err; + + while (bpf_map_get_next_key(map1_fd, &key, &next_key) == 0) { + err = bpf_map_lookup_elem(map2_fd, &next_key, val_buf); + if (err) + return err; + + key = next_key; + } + if (errno != ENOENT) + return -1; + + return 0; +} + +static void test_stacktrace_map() +{ + int control_map_fd, stackid_hmap_fd, stackmap_fd; + const char *file = "./test_stacktrace_map.o"; + int bytes, efd, err, pmu_fd, prog_fd; + struct perf_event_attr attr = {}; + __u32 key, val, duration = 0; + struct bpf_object *obj; + char buf[256]; + + err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd); + if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno)) + goto out; + + /* Get the ID for the sched/sched_switch tracepoint */ + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/sched/sched_switch/id"); + efd = open(buf, O_RDONLY, 0); + if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) + goto close_prog; + + bytes = read(efd, buf, sizeof(buf)); + close(efd); + if (CHECK(bytes <= 0 || bytes >= sizeof(buf), + "read", "bytes %d errno %d\n", bytes, errno)) + goto close_prog; + + /* Open the perf event and attach bpf progrram */ + attr.config = strtol(buf, NULL, 0); + attr.type = PERF_TYPE_TRACEPOINT; + attr.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN; + attr.sample_period = 1; + attr.wakeup_events = 1; + pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, + 0 /* cpu 0 */, -1 /* group id */, + 0 /* flags */); + if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n", + pmu_fd, errno)) + goto close_prog; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); + if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", + err, errno)) + goto close_pmu; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); + if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", + err, errno)) + goto disable_pmu; + + /* find map fds */ + control_map_fd = bpf_find_map(__func__, obj, "control_map"); + if (CHECK(control_map_fd < 0, "bpf_find_map control_map", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + stackid_hmap_fd = bpf_find_map(__func__, obj, "stackid_hmap"); + if (CHECK(stackid_hmap_fd < 0, "bpf_find_map stackid_hmap", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + stackmap_fd = bpf_find_map(__func__, obj, "stackmap"); + if (CHECK(stackmap_fd < 0, "bpf_find_map stackmap", "err %d errno %d\n", + err, errno)) + goto disable_pmu; + + /* give some time for bpf program run */ + sleep(1); + + /* disable stack trace collection */ + key = 0; + val = 1; + bpf_map_update_elem(control_map_fd, &key, &val, 0); + + /* for every element in stackid_hmap, we can find a corresponding one + * in stackmap, and vise versa. + */ + err = compare_map_keys(stackid_hmap_fd, stackmap_fd); + if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + err = compare_map_keys(stackmap_fd, stackid_hmap_fd); + if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap", + "err %d errno %d\n", err, errno)) + ; /* fall through */ + +disable_pmu: + ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE); + +close_pmu: + close(pmu_fd); + +close_prog: + bpf_object__close(obj); + +out: + return; +} + int main(void) { struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY }; @@ -852,6 +978,7 @@ int main(void) test_pkt_md_access(); test_obj_name(); test_tp_attach_query(); + test_stacktrace_map(); printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt); return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS; -- cgit v1.1