tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
Extension
.c
Size
4156 bytes
Lines
133
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
#include "test_stacktrace_build_id.skel.h"

void test_stacktrace_build_id_nmi(void)
{
	int control_map_fd, stackid_hmap_fd, stackmap_fd;
	struct test_stacktrace_build_id *skel;
	int err, pmu_fd;
	struct perf_event_attr attr = {
		.freq = 1,
		.type = PERF_TYPE_HARDWARE,
		.config = PERF_COUNT_HW_CPU_CYCLES,
	};
	__u32 key, prev_key, val, duration = 0;
	char buf[BPF_BUILD_ID_SIZE];
	struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
	int build_id_matches = 0, build_id_size;
	int i, retry = 1;

	attr.sample_freq = read_perf_max_sample_freq();

retry:
	skel = test_stacktrace_build_id__open();
	if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
		return;

	/* override program type */
	bpf_program__set_type(skel->progs.oncpu, BPF_PROG_TYPE_PERF_EVENT);

	err = test_stacktrace_build_id__load(skel);
	if (CHECK(err, "skel_load", "skeleton load failed: %d\n", err))
		goto cleanup;

	pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */,
			 0 /* cpu 0 */, -1 /* group id */,
			 0 /* flags */);
	if (pmu_fd < 0 && (errno == ENOENT || errno == EOPNOTSUPP)) {
		printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", __func__);
		test__skip();
		goto cleanup;
	}
	if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n",
		  pmu_fd, errno))
		goto cleanup;

	skel->links.oncpu = bpf_program__attach_perf_event(skel->progs.oncpu,
							   pmu_fd);
	if (!ASSERT_OK_PTR(skel->links.oncpu, "attach_perf_event")) {
		close(pmu_fd);
		goto cleanup;
	}

	/* find map fds */
	control_map_fd = bpf_map__fd(skel->maps.control_map);
	stackid_hmap_fd = bpf_map__fd(skel->maps.stackid_hmap);
	stackmap_fd = bpf_map__fd(skel->maps.stackmap);

	if (CHECK_FAIL(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")))
		goto cleanup;
	if (CHECK_FAIL(system("taskset 0x1 ./urandom_read 100000")))
		goto cleanup;
	/* 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 vice 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 cleanup;

	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 cleanup;

	build_id_size = read_build_id("urandom_read", buf, sizeof(buf));
	err = build_id_size < 0 ? build_id_size : 0;

	if (CHECK(err, "get build_id with readelf",
		  "err %d errno %d\n", err, errno))
		goto cleanup;

	err = bpf_map__get_next_key(skel->maps.stackmap, NULL, &key, sizeof(key));
	if (CHECK(err, "get_next_key from stackmap",
		  "err %d, errno %d\n", err, errno))

Annotation

Implementation Notes