From patchwork Tue Mar 13 21:47:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 885515 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@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="GKuuASzy"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4017kr3PbYz9sVD for ; Wed, 14 Mar 2018 08:48:04 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932205AbeCMVr6 (ORCPT ); Tue, 13 Mar 2018 17:47:58 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:36052 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753074AbeCMVrx (ORCPT ); Tue, 13 Mar 2018 17:47:53 -0400 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.22/8.16.0.22) with SMTP id w2DLhRih031958 for ; Tue, 13 Mar 2018 14:47:53 -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=ZwMtIVNlOQfhgE/LwbnTvRy/G3Uo/5Y+jglxv8Q5Tb0=; b=GKuuASzykHY6j2DDQ2UBw4bg173+0suASIHnyLR49gATO9dOSzRROWWpmhEK0uma+L3z mUZeEJDZD0jyNWhQWX9C1xFQSABKh7llca6zL5i9mqFGQ+lsbCvq2+QvBzXyxX/goHBc Vw+jKDptYMPVs06Zwn6qJcc4k6v4ApBZUIA= Received: from mail.thefacebook.com ([199.201.64.23]) by m0089730.ppops.net with ESMTP id 2gpm4c0nrd-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Tue, 13 Mar 2018 14:47:53 -0700 Received: from mx-out.facebook.com (192.168.52.123) by PRN-CHUB09.TheFacebook.com (192.168.16.19) with Microsoft SMTP Server id 14.3.361.1; Tue, 13 Mar 2018 14:47:51 -0700 Received: by devbig102.frc2.facebook.com (Postfix, from userid 4523) id 2CFF342826E4; Tue, 13 Mar 2018 14:47:50 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig102.frc2.facebook.com To: , , , CC: , , , Song Liu Smtp-Origin-Cluster: frc2c02 Subject: [PATCH bpf-next v5 2/2] bpf: add selftest for stackmap with BPF_F_STACK_BUILD_ID Date: Tue, 13 Mar 2018 14:47:46 -0700 Message-ID: <20180313214747.3675581-3-songliubraving@fb.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20180313214747.3675581-1-songliubraving@fb.com> References: <20180313214747.3675581-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-03-13_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 test_stacktrace_build_id() is added. It accesses tracepoint urandom_read with "dd" and "urandom_read" and gathers stack traces. Then it reads the stack traces from the stackmap. urandom_read is a statically link binary that reads from /dev/urandom. test_stacktrace_build_id() calls readelf to read build ID of urandom_read and compares it with build ID from the stackmap. Signed-off-by: Song Liu --- tools/include/uapi/linux/bpf.h | 22 +++ tools/testing/selftests/bpf/Makefile | 12 +- tools/testing/selftests/bpf/test_progs.c | 164 ++++++++++++++++++++- .../selftests/bpf/test_stacktrace_build_id.c | 60 ++++++++ tools/testing/selftests/bpf/urandom_read.c | 22 +++ 5 files changed, 278 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/test_stacktrace_build_id.c create mode 100644 tools/testing/selftests/bpf/urandom_read.c diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index db6bdc3..1944d0a 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -231,6 +231,28 @@ enum bpf_attach_type { #define BPF_F_RDONLY (1U << 3) #define BPF_F_WRONLY (1U << 4) +/* Flag for stack_map, store build_id+offset instead of pointer */ +#define BPF_F_STACK_BUILD_ID (1U << 5) + +enum bpf_stack_build_id_status { + /* user space need an empty entry to identify end of a trace */ + BPF_STACK_BUILD_ID_EMPTY = 0, + /* with valid build_id and offset */ + BPF_STACK_BUILD_ID_VALID = 1, + /* couldn't get build_id, fallback to ip */ + BPF_STACK_BUILD_ID_IP = 2, +}; + +#define BPF_BUILD_ID_SIZE 20 +struct bpf_stack_build_id { + __s32 status; + unsigned char build_id[BPF_BUILD_ID_SIZE]; + union { + __u64 offset; + __u64 ip; + }; +}; + union bpf_attr { struct { /* anonymous struct used by BPF_MAP_CREATE command */ __u32 map_type; /* one of enum bpf_map_type */ diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 8567a858..b0d29fd 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -13,6 +13,14 @@ endif CFLAGS += -Wall -O2 -I$(APIDIR) -I$(LIBDIR) -I$(GENDIR) $(GENFLAGS) -I../../../include LDLIBS += -lcap -lelf -lrt -lpthread +TEST_CUSTOM_PROGS = $(OUTPUT)/urandom_read +all: $(TEST_CUSTOM_PROGS) + +$(TEST_CUSTOM_PROGS): urandom_read + +urandom_read: urandom_read.c + $(CC) -o $(TEST_CUSTOM_PROGS) -static $< + # Order correspond to 'make run_tests' order TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \ test_align test_verifier_log test_dev_cgroup test_tcpbpf_user @@ -21,7 +29,7 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test test_pkt_md_access.o test_xdp_redirect.o test_xdp_meta.o sockmap_parse_prog.o \ sockmap_verdict_prog.o dev_cgroup.o sample_ret0.o test_tracepoint.o \ test_l4lb_noinline.o test_xdp_noinline.o test_stacktrace_map.o \ - sample_map_ret0.o test_tcpbpf_kern.o + sample_map_ret0.o test_tcpbpf_kern.o test_stacktrace_build_id.o # Order correspond to 'make run_tests' order TEST_PROGS := test_kmod.sh \ @@ -74,3 +82,5 @@ $(OUTPUT)/%.o: %.c $(CLANG) $(CLANG_FLAGS) \ -O2 -target bpf -emit-llvm -c $< -o - | \ $(LLC) -march=bpf -mcpu=$(CPU) -filetype=obj -o $@ + +EXTRA_CLEAN := $(TEST_CUSTOM_PROGS) diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index 27ad540..e9df48b 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -841,7 +841,8 @@ static void test_tp_attach_query(void) static int compare_map_keys(int map1_fd, int map2_fd) { __u32 key, next_key; - char val_buf[PERF_MAX_STACK_DEPTH * sizeof(__u64)]; + char val_buf[PERF_MAX_STACK_DEPTH * + sizeof(struct bpf_stack_build_id)]; int err; err = bpf_map_get_next_key(map1_fd, NULL, &key); @@ -964,6 +965,166 @@ static void test_stacktrace_map() return; } +static int extract_build_id(char *build_id, size_t size) +{ + FILE *fp; + char *line = NULL; + size_t len = 0; + + fp = popen("readelf -n ./urandom_read | grep 'Build ID'", "r"); + if (fp == NULL) + return -1; + + if (getline(&line, &len, fp) == -1) + goto err; + fclose(fp); + + if (len > size) + len = size; + memcpy(build_id, line, len); + build_id[len] = '\0'; + return 0; +err: + fclose(fp); + return -1; +} + +static void test_stacktrace_build_id(void) +{ + int control_map_fd, stackid_hmap_fd, stackmap_fd; + const char *file = "./test_stacktrace_build_id.o"; + int bytes, efd, err, pmu_fd, prog_fd; + struct perf_event_attr attr = {}; + __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_TRACEPOINT, &obj, &prog_fd); + if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno)) + goto out; + + /* Get the ID for the sched/sched_switch tracepoint */ + snprintf(buf, sizeof(buf), + "/sys/kernel/debug/tracing/events/random/urandom_read/id"); + efd = open(buf, O_RDONLY, 0); + if (CHECK(efd < 0, "open", "err %d errno %d\n", efd, errno)) + goto close_prog; + + bytes = read(efd, buf, sizeof(buf)); + close(efd); + if (CHECK(bytes <= 0 || bytes >= sizeof(buf), + "read", "bytes %d errno %d\n", bytes, errno)) + goto close_prog; + + /* Open the perf event and attach bpf progrram */ + attr.config = strtol(buf, NULL, 0); + attr.type = PERF_TYPE_TRACEPOINT; + attr.sample_type = PERF_SAMPLE_RAW | PERF_SAMPLE_CALLCHAIN; + attr.sample_period = 1; + attr.wakeup_events = 1; + 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\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; + + assert(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null") + == 0); + assert(system("./urandom_read if=/dev/urandom of=/dev/zero count=4 2> /dev/null") == 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); + + CHECK(build_id_matches < 1, "build id match", + "Didn't find expected build ID from the map"); + +disable_pmu: + ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE); + +close_pmu: + close(pmu_fd); + +close_prog: + bpf_object__close(obj); + +out: + return; +} + int main(void) { test_pkt_access(); @@ -976,6 +1137,7 @@ int main(void) test_obj_name(); test_tp_attach_query(); test_stacktrace_map(); + test_stacktrace_build_id(); printf("Summary: %d PASSED, %d FAILED\n", pass_cnt, error_cnt); return error_cnt ? EXIT_FAILURE : EXIT_SUCCESS; diff --git a/tools/testing/selftests/bpf/test_stacktrace_build_id.c b/tools/testing/selftests/bpf/test_stacktrace_build_id.c new file mode 100644 index 0000000..b755bd7 --- /dev/null +++ b/tools/testing/selftests/bpf/test_stacktrace_build_id.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Facebook + +#include +#include "bpf_helpers.h" + +#ifndef PERF_MAX_STACK_DEPTH +#define PERF_MAX_STACK_DEPTH 127 +#endif + +struct bpf_map_def SEC("maps") control_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 1, +}; + +struct bpf_map_def SEC("maps") stackid_hmap = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(__u32), + .value_size = sizeof(__u32), + .max_entries = 10000, +}; + +struct bpf_map_def SEC("maps") stackmap = { + .type = BPF_MAP_TYPE_STACK_TRACE, + .key_size = sizeof(__u32), + .value_size = sizeof(struct bpf_stack_build_id) + * PERF_MAX_STACK_DEPTH, + .max_entries = 128, + .map_flags = BPF_F_STACK_BUILD_ID, +}; + +/* taken from /sys/kernel/debug/tracing/events/random/urandom_read/format */ +struct random_urandom_args { + unsigned long long pad; + int got_bits; + int pool_left; + int input_left; +}; + +SEC("tracepoint/random/urandom_read") +int oncpu(struct random_urandom_args *args) +{ + __u32 key = 0, val = 0, *value_p; + + value_p = bpf_map_lookup_elem(&control_map, &key); + if (value_p && *value_p) + return 0; /* skip if non-zero *value_p */ + + /* The size of stackmap and stackid_hmap should be the same */ + key = bpf_get_stackid(args, &stackmap, BPF_F_USER_STACK); + if ((int)key >= 0) + bpf_map_update_elem(&stackid_hmap, &key, &val, 0); + + return 0; +} + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; /* ignored by tracepoints, required by libbpf.a */ diff --git a/tools/testing/selftests/bpf/urandom_read.c b/tools/testing/selftests/bpf/urandom_read.c new file mode 100644 index 0000000..4acfdeb --- /dev/null +++ b/tools/testing/selftests/bpf/urandom_read.c @@ -0,0 +1,22 @@ +#include +#include +#include +#include +#include +#include + +#define BUF_SIZE 256 +int main(void) +{ + int fd = open("/dev/urandom", O_RDONLY); + int i; + char buf[BUF_SIZE]; + + if (fd < 0) + return 1; + for (i = 0; i < 4; ++i) + read(fd, buf, BUF_SIZE); + + close(fd); + return 0; +}