From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95A7CC433F5 for ; Tue, 23 Nov 2021 20:01:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239609AbhKWUEZ convert rfc822-to-8bit (ORCPT ); Tue, 23 Nov 2021 15:04:25 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:41110 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239342AbhKWUEX (ORCPT ); Tue, 23 Nov 2021 15:04:23 -0500 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 1ANIdYkh030253 for ; Tue, 23 Nov 2021 12:01:14 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 3ch0vt34c3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 23 Nov 2021 12:01:13 -0800 Received: from intmgw001.37.frc1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Tue, 23 Nov 2021 12:01:12 -0800 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id 8766DA5FEC9A; Tue, 23 Nov 2021 12:01:08 -0800 (PST) From: Andrii Nakryiko To: , , CC: , , Song Liu Subject: [PATCH v2 bpf-next 2/2] selftests/bpf: mix legacy (maps) and modern (vars) BPF in one test Date: Tue, 23 Nov 2021 12:01:05 -0800 Message-ID: <20211123200105.387855-2-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211123200105.387855-1-andrii@kernel.org> References: <20211123200105.387855-1-andrii@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT X-FB-Internal: Safe Content-Type: text/plain X-FB-Source: Intern X-Proofpoint-ORIG-GUID: ucg3sR2t9LZl1guszfQCKsm7FK8m0foA X-Proofpoint-GUID: ucg3sR2t9LZl1guszfQCKsm7FK8m0foA X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.0.607.475 definitions=2021-11-23_07,2021-11-23_01,2020-04-07_01 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 suspectscore=0 bulkscore=0 mlxscore=0 impostorscore=0 clxscore=1015 spamscore=0 adultscore=0 phishscore=0 mlxlogscore=999 malwarescore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2111230098 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add selftest that combines two BPF programs within single BPF object file such that one of the programs is using global variables, but can be skipped at runtime on old kernels that don't support global data. Another BPF program is written with the goal to be runnable on very old kernels and only relies on explicitly accessed BPF maps. Such test, run against old kernels (e.g., libbpf CI will run it against 4.9 kernel that doesn't support global data), allows to test the approach and ensure that libbpf doesn't make unnecessary assumption about necessary kernel features. Acked-by: Song Liu Signed-off-by: Andrii Nakryiko --- v1->v2: - added comments explaining why we need bpf_printk() (Song). .../selftests/bpf/prog_tests/legacy_printk.c | 65 +++++++++++++++++ .../selftests/bpf/progs/test_legacy_printk.c | 73 +++++++++++++++++++ 2 files changed, 138 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/legacy_printk.c create mode 100644 tools/testing/selftests/bpf/progs/test_legacy_printk.c diff --git a/tools/testing/selftests/bpf/prog_tests/legacy_printk.c b/tools/testing/selftests/bpf/prog_tests/legacy_printk.c new file mode 100644 index 000000000000..ec6e45f2a644 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/legacy_printk.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include +#include "test_legacy_printk.skel.h" + +static int execute_one_variant(bool legacy) +{ + struct test_legacy_printk *skel; + int err, zero = 0, my_pid = getpid(), res, map_fd; + + skel = test_legacy_printk__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return -errno; + + bpf_program__set_autoload(skel->progs.handle_legacy, legacy); + bpf_program__set_autoload(skel->progs.handle_modern, !legacy); + + err = test_legacy_printk__load(skel); + /* no ASSERT_OK, we expect one of two variants can fail here */ + if (err) + goto err_out; + + if (legacy) { + map_fd = bpf_map__fd(skel->maps.my_pid_map); + err = bpf_map_update_elem(map_fd, &zero, &my_pid, BPF_ANY); + if (!ASSERT_OK(err, "my_pid_map_update")) + goto err_out; + err = bpf_map_lookup_elem(map_fd, &zero, &res); + } else { + skel->bss->my_pid_var = my_pid; + } + + err = test_legacy_printk__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto err_out; + + usleep(1); /* trigger */ + + if (legacy) { + map_fd = bpf_map__fd(skel->maps.res_map); + err = bpf_map_lookup_elem(map_fd, &zero, &res); + if (!ASSERT_OK(err, "res_map_lookup")) + goto err_out; + } else { + res = skel->bss->res_var; + } + + if (!ASSERT_GT(res, 0, "res")) { + err = -EINVAL; + goto err_out; + } + +err_out: + test_legacy_printk__destroy(skel); + return err; +} + +void test_legacy_printk(void) +{ + /* legacy variant should work everywhere */ + ASSERT_OK(execute_one_variant(true /* legacy */), "legacy_case"); + + /* execute modern variant, can fail the load on old kernels */ + execute_one_variant(false); +} diff --git a/tools/testing/selftests/bpf/progs/test_legacy_printk.c b/tools/testing/selftests/bpf/progs/test_legacy_printk.c new file mode 100644 index 000000000000..64c2d9ced529 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_legacy_printk.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include +#define BPF_NO_GLOBAL_DATA +#include + +char LICENSE[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, int); + __uint(max_entries, 1); +} my_pid_map SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, int); + __uint(max_entries, 1); +} res_map SEC(".maps"); + +volatile int my_pid_var = 0; +volatile int res_var = 0; + +SEC("tp/raw_syscalls/sys_enter") +int handle_legacy(void *ctx) +{ + int zero = 0, *my_pid, cur_pid, *my_res; + + my_pid = bpf_map_lookup_elem(&my_pid_map, &zero); + if (!my_pid) + return 1; + + cur_pid = bpf_get_current_pid_tgid() >> 32; + if (cur_pid != *my_pid) + return 1; + + my_res = bpf_map_lookup_elem(&res_map, &zero); + if (!my_res) + return 1; + + if (*my_res == 0) + /* use bpf_printk() in combination with BPF_NO_GLOBAL_DATA to + * force .rodata.str1.1 section that previously caused + * problems on old kernels due to libbpf always tried to + * create a global data map for it + */ + bpf_printk("Legacy-case bpf_printk test, pid %d\n", cur_pid); + *my_res = 1; + + return *my_res; +} + +SEC("tp/raw_syscalls/sys_enter") +int handle_modern(void *ctx) +{ + int zero = 0, cur_pid; + + cur_pid = bpf_get_current_pid_tgid() >> 32; + if (cur_pid != my_pid_var) + return 1; + + if (res_var == 0) + /* we need bpf_printk() to validate libbpf logic around unused + * global maps and legacy kernels; see comment in handle_legacy() + */ + bpf_printk("Modern-case bpf_printk test, pid %d\n", cur_pid); + res_var = 1; + + return res_var; +} -- 2.30.2