LXR linux/tools/testing/selftests/bpf/prog_tests/stacktrace_build

   1// SPDX-License-Identifier: GPL-2.0
   2#include <test_progs.h>
   3#include "test_stacktrace_build_id.skel.h"
   4
   5void test_stacktrace_build_id(void)
   6{
   7
   8        int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
   9        struct test_stacktrace_build_id *skel;
  10        int err, stack_trace_len;
  11        __u32 key, previous_key, val, duration = 0;
  12        char buf[256];
  13        int i, j;
  14        struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
  15        int build_id_matches = 0;
  16        int retry = 1;
  17
  18retry:
  19        skel = test_stacktrace_build_id__open_and_load();
  20        if (CHECK(!skel, "skel_open_and_load", "skeleton open/load failed\n"))
  21                return;
  22
  23        err = test_stacktrace_build_id__attach(skel);
  24        if (CHECK(err, "attach_tp", "err %d\n", err))
  25                goto cleanup;
  26
  27        /* find map fds */
  28        control_map_fd = bpf_map__fd(skel->maps.control_map);
  29        stackid_hmap_fd = bpf_map__fd(skel->maps.stackid_hmap);
  30        stackmap_fd = bpf_map__fd(skel->maps.stackmap);
  31        stack_amap_fd = bpf_map__fd(skel->maps.stack_amap);
  32
  33        if (CHECK_FAIL(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")))
  34                goto cleanup;
  35        if (CHECK_FAIL(system("./urandom_read")))
  36                goto cleanup;
  37        /* disable stack trace collection */
  38        key = 0;
  39        val = 1;
  40        bpf_map_update_elem(control_map_fd, &key, &val, 0);
  41
  42        /* for every element in stackid_hmap, we can find a corresponding one
  43         * in stackmap, and vise versa.
  44         */
  45        err = compare_map_keys(stackid_hmap_fd, stackmap_fd);
  46        if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap",
  47                  "err %d errno %d\n", err, errno))
  48                goto cleanup;
  49
  50        err = compare_map_keys(stackmap_fd, stackid_hmap_fd);
  51        if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap",
  52                  "err %d errno %d\n", err, errno))
  53                goto cleanup;
  54
  55        err = extract_build_id(buf, 256);
  56
  57        if (CHECK(err, "get build_id with readelf",
  58                  "err %d errno %d\n", err, errno))
  59                goto cleanup;
  60
  61        err = bpf_map_get_next_key(stackmap_fd, NULL, &key);
  62        if (CHECK(err, "get_next_key from stackmap",
  63                  "err %d, errno %d\n", err, errno))
  64                goto cleanup;
  65
  66        do {
  67                char build_id[64];
  68
  69                err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs);
  70                if (CHECK(err, "lookup_elem from stackmap",
  71                          "err %d, errno %d\n", err, errno))
  72                        goto cleanup;
  73                for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
  74                        if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
  75                            id_offs[i].offset != 0) {
  76                                for (j = 0; j < 20; ++j)
  77                                        sprintf(build_id + 2 * j, "%02x",
  78                                                id_offs[i].build_id[j] & 0xff);
  79                                if (strstr(buf, build_id) != NULL)
  80                                        build_id_matches = 1;
  81                        }
  82                previous_key = key;
  83        } while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0);
  84
  85        /* stack_map_get_build_id_offset() is racy and sometimes can return
  86         * BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
  87         * try it one more time.
  88         */
  89        if (build_id_matches < 1 && retry--) {
  90                test_stacktrace_build_id__destroy(skel);
  91                printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
  92                       __func__);
  93                goto retry;
  94        }
  95
  96        if (CHECK(build_id_matches < 1, "build id match",
  97                  "Didn't find expected build ID from the map\n"))
  98                goto cleanup;
  99
 100        stack_trace_len = PERF_MAX_STACK_DEPTH *
 101                          sizeof(struct bpf_stack_build_id);
 102        err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);
 103        CHECK(err, "compare_stack_ips stackmap vs. stack_amap",
 104              "err %d errno %d\n", err, errno);
 105
 106cleanup:
 107        test_stacktrace_build_id__destroy(skel);
 108}
 109