// SPDX-License-Identifier: GPL-2.0
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#include <test_progs.h>
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#include "test_stacktrace_build_id.skel.h"
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static __u64 read_perf_max_sample_freq(void)
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{
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__u64 sample_freq = 5000; /* fallback to 5000 on error */
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FILE *f;
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__u32 duration = 0;
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f = fopen("/proc/sys/kernel/perf_event_max_sample_rate", "r");
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if (f == NULL)
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return sample_freq;
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CHECK(fscanf(f, "%llu", &sample_freq) != 1, "Get max sample rate",
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"return default value: 5000,err %d\n", -errno);
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fclose(f);
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return sample_freq;
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}
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void test_stacktrace_build_id_nmi(void)
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{
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int control_map_fd, stackid_hmap_fd, stackmap_fd;
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struct test_stacktrace_build_id *skel;
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int err, pmu_fd;
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struct perf_event_attr attr = {
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.freq = 1,
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.type = PERF_TYPE_HARDWARE,
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.config = PERF_COUNT_HW_CPU_CYCLES,
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};
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__u32 key, previous_key, val, duration = 0;
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char buf[256];
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int i, j;
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struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
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int build_id_matches = 0;
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int retry = 1;
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attr.sample_freq = read_perf_max_sample_freq();
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retry:
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skel = test_stacktrace_build_id__open();
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if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
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return;
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/* override program type */
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bpf_program__set_perf_event(skel->progs.oncpu);
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err = test_stacktrace_build_id__load(skel);
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if (CHECK(err, "skel_load", "skeleton load failed: %d\n", err))
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goto cleanup;
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pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */,
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0 /* cpu 0 */, -1 /* group id */,
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0 /* flags */);
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if (pmu_fd < 0 && errno == ENOENT) {
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printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", __func__);
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test__skip();
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goto cleanup;
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}
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if (CHECK(pmu_fd < 0, "perf_event_open", "err %d errno %d\n",
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pmu_fd, errno))
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goto cleanup;
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skel->links.oncpu = bpf_program__attach_perf_event(skel->progs.oncpu,
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pmu_fd);
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if (CHECK(IS_ERR(skel->links.oncpu), "attach_perf_event",
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"err %ld\n", PTR_ERR(skel->links.oncpu))) {
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close(pmu_fd);
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goto cleanup;
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}
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/* find map fds */
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control_map_fd = bpf_map__fd(skel->maps.control_map);
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stackid_hmap_fd = bpf_map__fd(skel->maps.stackid_hmap);
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stackmap_fd = bpf_map__fd(skel->maps.stackmap);
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if (CHECK_FAIL(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")))
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goto cleanup;
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if (CHECK_FAIL(system("taskset 0x1 ./urandom_read 100000")))
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goto cleanup;
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/* disable stack trace collection */
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key = 0;
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val = 1;
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bpf_map_update_elem(control_map_fd, &key, &val, 0);
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/* for every element in stackid_hmap, we can find a corresponding one
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* in stackmap, and vise versa.
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*/
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err = compare_map_keys(stackid_hmap_fd, stackmap_fd);
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if (CHECK(err, "compare_map_keys stackid_hmap vs. stackmap",
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"err %d errno %d\n", err, errno))
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goto cleanup;
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err = compare_map_keys(stackmap_fd, stackid_hmap_fd);
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if (CHECK(err, "compare_map_keys stackmap vs. stackid_hmap",
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"err %d errno %d\n", err, errno))
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goto cleanup;
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err = extract_build_id(buf, 256);
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if (CHECK(err, "get build_id with readelf",
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"err %d errno %d\n", err, errno))
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goto cleanup;
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err = bpf_map_get_next_key(stackmap_fd, NULL, &key);
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if (CHECK(err, "get_next_key from stackmap",
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"err %d, errno %d\n", err, errno))
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goto cleanup;
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do {
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char build_id[64];
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err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs);
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if (CHECK(err, "lookup_elem from stackmap",
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"err %d, errno %d\n", err, errno))
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goto cleanup;
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for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
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if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
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id_offs[i].offset != 0) {
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for (j = 0; j < 20; ++j)
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sprintf(build_id + 2 * j, "%02x",
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id_offs[i].build_id[j] & 0xff);
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if (strstr(buf, build_id) != NULL)
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build_id_matches = 1;
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}
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previous_key = key;
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} while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0);
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/* stack_map_get_build_id_offset() is racy and sometimes can return
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* BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
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* try it one more time.
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*/
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if (build_id_matches < 1 && retry--) {
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test_stacktrace_build_id__destroy(skel);
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printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
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__func__);
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goto retry;
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}
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if (CHECK(build_id_matches < 1, "build id match",
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"Didn't find expected build ID from the map\n"))
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goto cleanup;
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/*
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* We intentionally skip compare_stack_ips(). This is because we
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* only support one in_nmi() ips-to-build_id translation per cpu
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* at any time, thus stack_amap here will always fallback to
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* BPF_STACK_BUILD_ID_IP;
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*/
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cleanup:
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test_stacktrace_build_id__destroy(skel);
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}
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