1 // SPDX-License-Identifier: GPL-2.0
2 #include <test_progs.h>
4 void test_stacktrace_build_id(void)
6 int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;
7 const char *prog_name = "tracepoint/random/urandom_read";
8 const char *file = "./test_stacktrace_build_id.o";
9 int err, prog_fd, stack_trace_len;
10 __u32 key, previous_key, val, duration = 0;
11 struct bpf_program *prog;
12 struct bpf_object *obj;
13 struct bpf_link *link = NULL;
16 struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
17 int build_id_matches = 0;
21 err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
22 if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno))
25 prog = bpf_object__find_program_by_title(obj, prog_name);
26 if (CHECK(!prog, "find_prog", "prog '%s' not found\n", prog_name))
29 link = bpf_program__attach_tracepoint(prog, "random", "urandom_read");
30 if (CHECK(IS_ERR(link), "attach_tp", "err %ld\n", PTR_ERR(link)))
34 control_map_fd = bpf_find_map(__func__, obj, "control_map");
35 if (CHECK(control_map_fd < 0, "bpf_find_map control_map",
36 "err %d errno %d\n", err, errno))
39 stackid_hmap_fd = bpf_find_map(__func__, obj, "stackid_hmap");
40 if (CHECK(stackid_hmap_fd < 0, "bpf_find_map stackid_hmap",
41 "err %d errno %d\n", err, errno))
44 stackmap_fd = bpf_find_map(__func__, obj, "stackmap");
45 if (CHECK(stackmap_fd < 0, "bpf_find_map stackmap", "err %d errno %d\n",
49 stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap");
50 if (CHECK(stack_amap_fd < 0, "bpf_find_map stack_amap",
51 "err %d errno %d\n", err, errno))
54 if (CHECK_FAIL(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")))
56 if (CHECK_FAIL(system("./urandom_read")))
58 /* disable stack trace collection */
61 bpf_map_update_elem(control_map_fd, &key, &val, 0);
63 /* for every element in stackid_hmap, we can find a corresponding one
64 * in stackmap, and vise versa.
66 err = compare_map_keys(stackid_hmap_fd, stackmap_fd);
67 if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap",
68 "err %d errno %d\n", err, errno))
71 err = compare_map_keys(stackmap_fd, stackid_hmap_fd);
72 if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap",
73 "err %d errno %d\n", err, errno))
76 err = extract_build_id(buf, 256);
78 if (CHECK(err, "get build_id with readelf",
79 "err %d errno %d\n", err, errno))
82 err = bpf_map_get_next_key(stackmap_fd, NULL, &key);
83 if (CHECK(err, "get_next_key from stackmap",
84 "err %d, errno %d\n", err, errno))
90 err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs);
91 if (CHECK(err, "lookup_elem from stackmap",
92 "err %d, errno %d\n", err, errno))
94 for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
95 if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
96 id_offs[i].offset != 0) {
97 for (j = 0; j < 20; ++j)
98 sprintf(build_id + 2 * j, "%02x",
99 id_offs[i].build_id[j] & 0xff);
100 if (strstr(buf, build_id) != NULL)
101 build_id_matches = 1;
104 } while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0);
106 /* stack_map_get_build_id_offset() is racy and sometimes can return
107 * BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
108 * try it one more time.
110 if (build_id_matches < 1 && retry--) {
111 bpf_link__destroy(link);
112 bpf_object__close(obj);
113 printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
118 if (CHECK(build_id_matches < 1, "build id match",
119 "Didn't find expected build ID from the map\n"))
122 stack_trace_len = PERF_MAX_STACK_DEPTH
123 * sizeof(struct bpf_stack_build_id);
124 err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);
125 CHECK(err, "compare_stack_ips stackmap vs. stack_amap",
126 "err %d errno %d\n", err, errno);
129 bpf_link__destroy(link);
132 bpf_object__close(obj);