1 // SPDX-License-Identifier: GPL-2.0
2 #include <test_progs.h>
3 #include "test_stacktrace_build_id.skel.h"
4
test_stacktrace_build_id_nmi(void)5 void test_stacktrace_build_id_nmi(void)
6 {
7 int control_map_fd, stackid_hmap_fd, stackmap_fd;
8 struct test_stacktrace_build_id *skel;
9 int err, pmu_fd;
10 struct perf_event_attr attr = {
11 .freq = 1,
12 .type = PERF_TYPE_HARDWARE,
13 .config = PERF_COUNT_HW_CPU_CYCLES,
14 };
15 __u32 key, prev_key, val, duration = 0;
16 char buf[256];
17 int i, j;
18 struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
19 int build_id_matches = 0;
20 int retry = 1;
21
22 attr.sample_freq = read_perf_max_sample_freq();
23
24 retry:
25 skel = test_stacktrace_build_id__open();
26 if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
27 return;
28
29 /* override program type */
30 bpf_program__set_type(skel->progs.oncpu, BPF_PROG_TYPE_PERF_EVENT);
31
32 err = test_stacktrace_build_id__load(skel);
33 if (CHECK(err, "skel_load", "skeleton load failed: %d\n", err))
34 goto cleanup;
35
36 pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */,
37 0 /* cpu 0 */, -1 /* group id */,
38 0 /* flags */);
39 if (pmu_fd < 0 && errno == ENOENT) {
40 printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", __func__);
41 test__skip();
42 goto cleanup;
43 }
44 if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n",
45 pmu_fd, errno))
46 goto cleanup;
47
48 skel->links.oncpu = bpf_program__attach_perf_event(skel->progs.oncpu,
49 pmu_fd);
50 if (!ASSERT_OK_PTR(skel->links.oncpu, "attach_perf_event")) {
51 close(pmu_fd);
52 goto cleanup;
53 }
54
55 /* find map fds */
56 control_map_fd = bpf_map__fd(skel->maps.control_map);
57 stackid_hmap_fd = bpf_map__fd(skel->maps.stackid_hmap);
58 stackmap_fd = bpf_map__fd(skel->maps.stackmap);
59
60 if (CHECK_FAIL(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")))
61 goto cleanup;
62 if (CHECK_FAIL(system("taskset 0x1 ./urandom_read 100000")))
63 goto cleanup;
64 /* disable stack trace collection */
65 key = 0;
66 val = 1;
67 bpf_map_update_elem(control_map_fd, &key, &val, 0);
68
69 /* for every element in stackid_hmap, we can find a corresponding one
70 * in stackmap, and vise versa.
71 */
72 err = compare_map_keys(stackid_hmap_fd, stackmap_fd);
73 if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap",
74 "err %d errno %d\n", err, errno))
75 goto cleanup;
76
77 err = compare_map_keys(stackmap_fd, stackid_hmap_fd);
78 if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap",
79 "err %d errno %d\n", err, errno))
80 goto cleanup;
81
82 err = extract_build_id(buf, 256);
83
84 if (CHECK(err, "get build_id with readelf",
85 "err %d errno %d\n", err, errno))
86 goto cleanup;
87
88 err = bpf_map__get_next_key(skel->maps.stackmap, NULL, &key, sizeof(key));
89 if (CHECK(err, "get_next_key from stackmap",
90 "err %d, errno %d\n", err, errno))
91 goto cleanup;
92
93 do {
94 char build_id[64];
95
96 err = bpf_map__lookup_elem(skel->maps.stackmap, &key, sizeof(key),
97 id_offs, sizeof(id_offs), 0);
98 if (CHECK(err, "lookup_elem from stackmap",
99 "err %d, errno %d\n", err, errno))
100 goto cleanup;
101 for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
102 if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
103 id_offs[i].offset != 0) {
104 for (j = 0; j < 20; ++j)
105 sprintf(build_id + 2 * j, "%02x",
106 id_offs[i].build_id[j] & 0xff);
107 if (strstr(buf, build_id) != NULL)
108 build_id_matches = 1;
109 }
110 prev_key = key;
111 } while (bpf_map__get_next_key(skel->maps.stackmap, &prev_key, &key, sizeof(key)) == 0);
112
113 /* stack_map_get_build_id_offset() is racy and sometimes can return
114 * BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
115 * try it one more time.
116 */
117 if (build_id_matches < 1 && retry--) {
118 test_stacktrace_build_id__destroy(skel);
119 printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
120 __func__);
121 goto retry;
122 }
123
124 if (CHECK(build_id_matches < 1, "build id match",
125 "Didn't find expected build ID from the map\n"))
126 goto cleanup;
127
128 /*
129 * We intentionally skip compare_stack_ips(). This is because we
130 * only support one in_nmi() ips-to-build_id translation per cpu
131 * at any time, thus stack_amap here will always fallback to
132 * BPF_STACK_BUILD_ID_IP;
133 */
134
135 cleanup:
136 test_stacktrace_build_id__destroy(skel);
137 }
138