diff options
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c')
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c new file mode 100644 index 000000000000..3aab2b083c71 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <test_progs.h> + +void test_stacktrace_build_id(void) +{ + int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd; + const char *file = "./test_stacktrace_build_id.o"; + int bytes, efd, err, pmu_fd, prog_fd, stack_trace_len; + struct perf_event_attr attr = {}; + __u32 key, previous_key, val, duration = 0; + struct bpf_object *obj; + char buf[256]; + int i, j; + struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH]; + int build_id_matches = 0; + int retry = 1; + +retry: + 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/random/urandom_read/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; + + stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap"); + if (CHECK(stack_amap_fd < 0, "bpf_find_map stack_amap", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + assert(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null") + == 0); + assert(system("./urandom_read") == 0); + /* 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)) + goto disable_pmu; + + err = extract_build_id(buf, 256); + + if (CHECK(err, "get build_id with readelf", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + err = bpf_map_get_next_key(stackmap_fd, NULL, &key); + if (CHECK(err, "get_next_key from stackmap", + "err %d, errno %d\n", err, errno)) + goto disable_pmu; + + do { + char build_id[64]; + + err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs); + if (CHECK(err, "lookup_elem from stackmap", + "err %d, errno %d\n", err, errno)) + goto disable_pmu; + for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i) + if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID && + id_offs[i].offset != 0) { + for (j = 0; j < 20; ++j) + sprintf(build_id + 2 * j, "%02x", + id_offs[i].build_id[j] & 0xff); + if (strstr(buf, build_id) != NULL) + build_id_matches = 1; + } + previous_key = key; + } while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0); + + /* stack_map_get_build_id_offset() is racy and sometimes can return + * BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID; + * try it one more time. + */ + if (build_id_matches < 1 && retry--) { + ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE); + close(pmu_fd); + bpf_object__close(obj); + printf("%s:WARN:Didn't find expected build ID from the map, retrying\n", + __func__); + goto retry; + } + + if (CHECK(build_id_matches < 1, "build id match", + "Didn't find expected build ID from the map\n")) + goto disable_pmu; + + stack_trace_len = PERF_MAX_STACK_DEPTH + * sizeof(struct bpf_stack_build_id); + err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len); + CHECK(err, "compare_stack_ips stackmap vs. stack_amap", + "err %d errno %d\n", err, errno); + +disable_pmu: + ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE); + +close_pmu: + close(pmu_fd); + +close_prog: + bpf_object__close(obj); + +out: + return; +} |