1 files changed, 137 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
new file mode 100644
index 000000000..704f7f6c3
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/stacktrace_build_id_nmi.c
@@ -0,0 +1,137 @@
+// 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[256];
+	int i, j;
+	struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
+	int build_id_matches = 0;
+	int 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) {
+		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 vise 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;
+
+	err = extract_build_id(buf, 256);
+
+	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))
+		goto cleanup;
+
+	do {
+		char build_id[64];
+
+		err = bpf_map__lookup_elem(skel->maps.stackmap, &key, sizeof(key),
+					   id_offs, sizeof(id_offs), 0);
+		if (CHECK(err, "lookup_elem from stackmap",
+			  "err %d, errno %d\n", err, errno))
+			goto cleanup;
+		for (i = 0; i < PERF_MAX_STACK_DEPTH; ++i)
+			if (id_offs[i].status == BPF_STACK_BUILD_ID_VALID &&
+			    id_offs[i].offset != 0) {
+				for (j = 0; j < 20; ++j)
+					sprintf(build_id + 2 * j, "%02x",
+						id_offs[i].build_id[j] & 0xff);
+				if (strstr(buf, build_id) != NULL)
+					build_id_matches = 1;
+			}
+		prev_key = key;
+	} while (bpf_map__get_next_key(skel->maps.stackmap, &prev_key, &key, sizeof(key)) == 0);
+
+	/* stack_map_get_build_id_offset() is racy and sometimes can return
+	 * BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
+	 * try it one more time.
+	 */
+	if (build_id_matches < 1 && retry--) {
+		test_stacktrace_build_id__destroy(skel);
+		printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
+		       __func__);
+		goto retry;
+	}
+
+	if (CHECK(build_id_matches < 1, "build id match",
+		  "Didn't find expected build ID from the map\n"))
+		goto cleanup;
+
+	/*
+	 * We intentionally skip compare_stack_ips(). This is because we
+	 * only support one in_nmi() ips-to-build_id translation per cpu
+	 * at any time, thus stack_amap here will always fallback to
+	 * BPF_STACK_BUILD_ID_IP;
+	 */
+
+cleanup:
+	test_stacktrace_build_id__destroy(skel);
+}