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