From patchwork Wed May 2 23:20:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 907776 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="f8oO2mMN"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 40bvQp6fRcz9s4n for ; Thu, 3 May 2018 09:20:50 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751842AbeEBXUs (ORCPT ); Wed, 2 May 2018 19:20:48 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:39652 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751694AbeEBXUm (ORCPT ); Wed, 2 May 2018 19:20:42 -0400 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w42NIETa021044 for ; Wed, 2 May 2018 16:20:40 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=i4a6nP+NfS4bHLL0EeTIWBKUwRRBnmW/6yHklac5Hmw=; b=f8oO2mMN0hPdZB5GLz/hQQIE280pcmfz4nr9ZRugedwhS/hTv1wp73nXIthwpg+rwEid 7HlPhEfN2Ra4Nhoh61EGBQcZ0EM7SujjIbbUwR9Z9teEy++MZJBYrYO0B2wc0MQNMlzR Ci/PiCLXTl1hlPOHBsIAmirgrYPHlmlK2Ro= Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2hqm0h0gcw-2 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 02 May 2018 16:20:40 -0700 Received: from mx-out.facebook.com (192.168.52.123) by PRN-CHUB11.TheFacebook.com (192.168.16.21) with Microsoft SMTP Server id 14.3.319.2; Wed, 2 May 2018 16:20:39 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 61C9A62E14C0; Wed, 2 May 2018 16:20:39 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig006.ftw2.facebook.com To: CC: Song Liu , , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v2 bpf-next 2/2] bpf: add selftest for stackmap with build_id in NMI context Date: Wed, 2 May 2018 16:20:30 -0700 Message-ID: <20180502232030.3788284-3-songliubraving@fb.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20180502232030.3788284-1-songliubraving@fb.com> References: <20180502232030.3788284-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-05-02_09:, , signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This new test captures stackmap with build_id with hardware event PERF_COUNT_HW_CPU_CYCLES. Because we only support one ips-to-build_id lookup per cpu in NMI context, stack_amap will not be able to do the lookup in this test. Therefore, we didn't do compare_stack_ips(), as it will alwasy fail. urandom_read.c is extended to run configurable cycles so that it can be caught by the perf event. Signed-off-by: Song Liu --- tools/testing/selftests/bpf/test_progs.c | 137 +++++++++++++++++++++++++++++ tools/testing/selftests/bpf/urandom_read.c | 10 ++- 2 files changed, 145 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index aa336f0..00bb08c 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -1272,6 +1272,142 @@ static void test_stacktrace_build_id(void) return; } +static void test_stacktrace_build_id_nmi(void) +{ + int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd; + const char *file = "./test_stacktrace_build_id.o"; + int err, pmu_fd, prog_fd; + struct perf_event_attr attr = { + .sample_freq = 5000, + .freq = 1, + .type = PERF_TYPE_HARDWARE, + .config = PERF_COUNT_HW_CPU_CYCLES, + }; + __u32 key, previous_key, val, duration = 0; + struct bpf_object *obj; + char buf[256]; + int i, j; + struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH]; + int build_id_matches = 0; + + err = bpf_prog_load(file, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd); + if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno)) + goto out; + + pmu_fd = syscall(__NR_perf_event_open, &attr, -1 /* pid */, + 0 /* cpu 0 */, -1 /* group id */, + 0 /* flags */); + if (CHECK(pmu_fd < 0, "perf_event_open", + "err %d errno %d. Does the test host support PERF_COUNT_HW_CPU_CYCLES?\n", + pmu_fd, errno)) + goto close_prog; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0); + if (CHECK(err, "perf_event_ioc_enable", "err %d errno %d\n", + err, errno)) + goto close_pmu; + + err = ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd); + if (CHECK(err, "perf_event_ioc_set_bpf", "err %d errno %d\n", + err, errno)) + goto disable_pmu; + + /* find map fds */ + control_map_fd = bpf_find_map(__func__, obj, "control_map"); + if (CHECK(control_map_fd < 0, "bpf_find_map control_map", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + stackid_hmap_fd = bpf_find_map(__func__, obj, "stackid_hmap"); + if (CHECK(stackid_hmap_fd < 0, "bpf_find_map stackid_hmap", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + stackmap_fd = bpf_find_map(__func__, obj, "stackmap"); + if (CHECK(stackmap_fd < 0, "bpf_find_map stackmap", "err %d errno %d\n", + err, errno)) + goto disable_pmu; + + stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap"); + if (CHECK(stack_amap_fd < 0, "bpf_find_map stack_amap", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + assert(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null") + == 0); + assert(system("taskset 0x1 ./urandom_read 100000") == 0); + /* 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 disable_pmu; + + 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 disable_pmu; + + err = extract_build_id(buf, 256); + + if (CHECK(err, "get build_id with readelf", + "err %d errno %d\n", err, errno)) + goto disable_pmu; + + err = bpf_map_get_next_key(stackmap_fd, NULL, &key); + if (CHECK(err, "get_next_key from stackmap", + "err %d, errno %d\n", err, errno)) + goto disable_pmu; + + do { + char build_id[64]; + + err = bpf_map_lookup_elem(stackmap_fd, &key, id_offs); + if (CHECK(err, "lookup_elem from stackmap", + "err %d, errno %d\n", err, errno)) + goto disable_pmu; + 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; + } + previous_key = key; + } while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0); + + if (CHECK(build_id_matches < 1, "build id match", + "Didn't find expected build ID from the map\n")) + goto disable_pmu; + + /* + * 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; + */ + +disable_pmu: + ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE); + +close_pmu: + close(pmu_fd); + +close_prog: + bpf_object__close(obj); + +out: + return; +} + #define MAX_CNT_RAWTP 10ull #define MAX_STACK_RAWTP 100 struct get_stack_trace_t { @@ -1425,6 +1561,7 @@ int main(void) test_tp_attach_query(); test_stacktrace_map(); test_stacktrace_build_id(); + test_stacktrace_build_id_nmi(); test_stacktrace_map_raw_tp(); test_get_stack_raw_tp(); diff --git a/tools/testing/selftests/bpf/urandom_read.c b/tools/testing/selftests/bpf/urandom_read.c index 4acfdeb..9de8b7c 100644 --- a/tools/testing/selftests/bpf/urandom_read.c +++ b/tools/testing/selftests/bpf/urandom_read.c @@ -6,15 +6,21 @@ #include #define BUF_SIZE 256 -int main(void) + +int main(int argc, char *argv[]) { int fd = open("/dev/urandom", O_RDONLY); int i; char buf[BUF_SIZE]; + int count = 4; if (fd < 0) return 1; - for (i = 0; i < 4; ++i) + + if (argc == 2) + count = atoi(argv[1]); + + for (i = 0; i < count; ++i) read(fd, buf, BUF_SIZE); close(fd);