| // 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; |
| } |