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 7BB13C433F5 for ; Fri, 25 Mar 2022 05:30:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354825AbiCYFbl convert rfc822-to-8bit (ORCPT ); Fri, 25 Mar 2022 01:31:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354971AbiCYFbj (ORCPT ); Fri, 25 Mar 2022 01:31:39 -0400 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27A53583AC for ; Thu, 24 Mar 2022 22:30:05 -0700 (PDT) Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 22P0IX0P027067 for ; Thu, 24 Mar 2022 22:30:05 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3f02uw6mt9-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 24 Mar 2022 22:30:04 -0700 Received: from twshared1376.03.prn5.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Thu, 24 Mar 2022 22:30:02 -0700 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id B707614CB0BA0; Thu, 24 Mar 2022 22:29:57 -0700 (PDT) From: Andrii Nakryiko To: , , CC: , , Alan Maguire , Dave Marchevsky Subject: [PATCH bpf-next 6/7] selftests/bpf: add basic USDT selftests Date: Thu, 24 Mar 2022 22:29:40 -0700 Message-ID: <20220325052941.3526715-7-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220325052941.3526715-1-andrii@kernel.org> References: <20220325052941.3526715-1-andrii@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-ORIG-GUID: LCo2qqvDAOIZ08kBwAsw5eR15o7_2GKc X-Proofpoint-GUID: LCo2qqvDAOIZ08kBwAsw5eR15o7_2GKc X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-25_01,2022-03-24_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add semaphore-based USDT to test_progs itself and write basic tests to valicate both auto-attachment and manual attachment logic, as well as BPF-side functionality. Also add subtests to validate that libbpf properly deduplicates USDT specs and handles spec overflow situations correctly, as well as proper "rollback" of partially-attached multi-spec USDT. Signed-off-by: Andrii Nakryiko --- tools/testing/selftests/bpf/Makefile | 1 + tools/testing/selftests/bpf/prog_tests/usdt.c | 314 ++++++++++++++++++ tools/testing/selftests/bpf/progs/test_usdt.c | 115 +++++++ 3 files changed, 430 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/usdt.c create mode 100644 tools/testing/selftests/bpf/progs/test_usdt.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 3820608faf57..18e22def3bdb 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -400,6 +400,7 @@ $(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.o: \ $(TRUNNER_BPF_PROGS_DIR)/*.h \ $$(INCLUDE_DIR)/vmlinux.h \ $(wildcard $(BPFDIR)/bpf_*.h) \ + $(wildcard $(BPFDIR)/*.bpf.h) \ | $(TRUNNER_OUTPUT) $$(BPFOBJ) $$(call $(TRUNNER_BPF_BUILD_RULE),$$<,$$@, \ $(TRUNNER_BPF_CFLAGS)) diff --git a/tools/testing/selftests/bpf/prog_tests/usdt.c b/tools/testing/selftests/bpf/prog_tests/usdt.c new file mode 100644 index 000000000000..44a20d8c45d7 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/usdt.c @@ -0,0 +1,314 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ +#include + +#define _SDT_HAS_SEMAPHORES 1 +#include + +#include "test_usdt.skel.h" +#include "test_urandom_usdt.skel.h" + +int lets_test_this(int); + +static volatile int idx = 2; +static volatile __u64 bla = 0xFEDCBA9876543210ULL; +static volatile short nums[] = {-1, -2, -3, }; + +static volatile struct { + int x; + signed char y; +} t1 = { 1, -127 }; + +#define SEC(name) __attribute__((section(name), used)) + +unsigned short test_usdt0_semaphore SEC(".probes"); +unsigned short test_usdt3_semaphore SEC(".probes"); +unsigned short test_usdt12_semaphore SEC(".probes"); + +static void __always_inline trigger_func(int x) { + long y = 42; + + if (test_usdt0_semaphore) + STAP_PROBE(test, usdt0); + if (test_usdt3_semaphore) + STAP_PROBE3(test, usdt3, x, y, &bla); + if (test_usdt12_semaphore) { + STAP_PROBE12(test, usdt12, + x, x + 1, y, x + y, 5, + y / 7, bla, &bla, -9, nums[x], + nums[idx], t1.y); + } +} + +static void subtest_basic_usdt(void) +{ + LIBBPF_OPTS(bpf_usdt_opts, opts); + struct test_usdt *skel; + struct test_usdt__bss *bss; + int err; + + skel = test_usdt__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bss = skel->bss; + bss->my_pid = getpid(); + + err = test_usdt__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* usdt0 won't be auto-attached */ + opts.usdt_cookie = 0xcafedeadbeeffeed; + skel->links.usdt0 = bpf_program__attach_usdt(skel->progs.usdt0, + 0 /*self*/, "/proc/self/exe", + "test", "usdt0", &opts); + if (!ASSERT_OK_PTR(skel->links.usdt0, "usdt0_link")) + goto cleanup; + + trigger_func(1); + + ASSERT_EQ(bss->usdt0_called, 1, "usdt0_called"); + ASSERT_EQ(bss->usdt3_called, 1, "usdt3_called"); + ASSERT_EQ(bss->usdt12_called, 1, "usdt12_called"); + + ASSERT_EQ(bss->usdt0_cookie, 0xcafedeadbeeffeed, "usdt0_cookie"); + ASSERT_EQ(bss->usdt0_arg_cnt, 0, "usdt0_arg_cnt"); + ASSERT_EQ(bss->usdt0_arg_ret, -ENOENT, "usdt0_arg_ret"); + + /* auto-attached usdt3 gets default zero cookie value */ + ASSERT_EQ(bss->usdt3_cookie, 0, "usdt3_cookie"); + ASSERT_EQ(bss->usdt3_arg_cnt, 3, "usdt3_arg_cnt"); + + ASSERT_EQ(bss->usdt3_arg_rets[0], 0, "usdt3_arg1_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[1], 0, "usdt3_arg2_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[2], 0, "usdt3_arg3_ret"); + ASSERT_EQ(bss->usdt3_args[0], 1, "usdt3_arg1"); + ASSERT_EQ(bss->usdt3_args[1], 42, "usdt3_arg2"); + ASSERT_EQ(bss->usdt3_args[2], (uintptr_t)&bla, "usdt3_arg3"); + + /* auto-attached usdt12 gets default zero cookie value */ + ASSERT_EQ(bss->usdt12_cookie, 0, "usdt12_cookie"); + ASSERT_EQ(bss->usdt12_arg_cnt, 12, "usdt12_arg_cnt"); + + ASSERT_EQ(bss->usdt12_args[0], 1, "usdt12_arg1"); + ASSERT_EQ(bss->usdt12_args[1], 1 + 1, "usdt12_arg2"); + ASSERT_EQ(bss->usdt12_args[2], 42, "usdt12_arg3"); + ASSERT_EQ(bss->usdt12_args[3], 42 + 1, "usdt12_arg4"); + ASSERT_EQ(bss->usdt12_args[4], 5, "usdt12_arg5"); + ASSERT_EQ(bss->usdt12_args[5], 42 / 7, "usdt12_arg6"); + ASSERT_EQ(bss->usdt12_args[6], bla, "usdt12_arg7"); + ASSERT_EQ(bss->usdt12_args[7], (uintptr_t)&bla, "usdt12_arg8"); + ASSERT_EQ(bss->usdt12_args[8], -9, "usdt12_arg9"); + ASSERT_EQ(bss->usdt12_args[9], nums[1], "usdt12_arg10"); + ASSERT_EQ(bss->usdt12_args[10], nums[idx], "usdt12_arg11"); + ASSERT_EQ(bss->usdt12_args[11], t1.y, "usdt12_arg12"); + + /* trigger_func() is marked __always_inline, so USDT invocations will be + * inlined in two different places, meaning that each USDT will have + * at least 2 different places to be attached to. This verifies that + * bpf_program__attach_usdt() handles this properly and attaches to + * all possible places of USDT invocation. + */ + trigger_func(2); + + ASSERT_EQ(bss->usdt0_called, 2, "usdt0_called"); + ASSERT_EQ(bss->usdt3_called, 2, "usdt3_called"); + ASSERT_EQ(bss->usdt12_called, 2, "usdt12_called"); + + /* only check values that depend on trigger_func()'s input value */ + ASSERT_EQ(bss->usdt3_args[0], 2, "usdt3_arg1"); + + ASSERT_EQ(bss->usdt12_args[0], 2, "usdt12_arg1"); + ASSERT_EQ(bss->usdt12_args[1], 2 + 1, "usdt12_arg2"); + ASSERT_EQ(bss->usdt12_args[3], 42 + 2, "usdt12_arg4"); + ASSERT_EQ(bss->usdt12_args[9], nums[2], "usdt12_arg10"); + + /* detach and re-attach usdt3 */ + bpf_link__destroy(skel->links.usdt3); + + opts.usdt_cookie = 0xBADC00C51E; + skel->links.usdt3 = bpf_program__attach_usdt(skel->progs.usdt3, -1 /* any pid */, + "/proc/self/exe", "test", "usdt3", &opts); + if (!ASSERT_OK_PTR(skel->links.usdt3, "usdt3_reattach")) + goto cleanup; + + trigger_func(3); + + ASSERT_EQ(bss->usdt3_called, 3, "usdt3_called"); + /* this time usdt3 has custom cookie */ + ASSERT_EQ(bss->usdt3_cookie, 0xBADC00C51E, "usdt3_cookie"); + ASSERT_EQ(bss->usdt3_arg_cnt, 3, "usdt3_arg_cnt"); + + ASSERT_EQ(bss->usdt3_arg_rets[0], 0, "usdt3_arg1_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[1], 0, "usdt3_arg2_ret"); + ASSERT_EQ(bss->usdt3_arg_rets[2], 0, "usdt3_arg3_ret"); + ASSERT_EQ(bss->usdt3_args[0], 3, "usdt3_arg1"); + ASSERT_EQ(bss->usdt3_args[1], 42, "usdt3_arg2"); + ASSERT_EQ(bss->usdt3_args[2], (uintptr_t)&bla, "usdt3_arg3"); + +cleanup: + test_usdt__destroy(skel); +} + +unsigned short test_usdt_100_semaphore SEC(".probes"); +unsigned short test_usdt_300_semaphore SEC(".probes"); +unsigned short test_usdt_400_semaphore SEC(".probes"); + +#define R10(F, X) F(X+0); F(X+1);F(X+2); F(X+3); F(X+4); \ + F(X+5); F(X+6); F(X+7); F(X+8); F(X+9); +#define R100(F, X) R10(F,X+ 0);R10(F,X+10);R10(F,X+20);R10(F,X+30);R10(F,X+40); \ + R10(F,X+50);R10(F,X+60);R10(F,X+70);R10(F,X+80);R10(F,X+90); + +/* carefully control that we get exactly 100 inlines by preventing inlining */ +static void __always_inline f100(int x) +{ + STAP_PROBE1(test, usdt_100, x); +} + +__weak void trigger_100_usdts(void) +{ + R100(f100, 0); +} + +/* we shouldn't be able to attach to test:usdt2_300 USDT as we don't have as + * many slots for specs. It's important that each STAP_PROBE2() invocation + * (after untolling) gets different arg spec due to compiler inlining i as + * a constant + */ +static void __always_inline f300(int x) +{ + STAP_PROBE1(test, usdt_300, x); +} + +__weak void trigger_300_usdts(void) +{ + R100(f300, 0); + R100(f300, 100); + R100(f300, 200); +} + +static void __always_inline f400(int /*unused*/ ) +{ + static int x; + + STAP_PROBE1(test, usdt_400, x++); +} + +/* this time we have 400 different USDT call sites, but they have uniform + * argument location, so libbpf's spec string deduplication logic should keep + * spec count use very small and so we should be able to attach to all 400 + * call sites + */ +__weak void trigger_400_usdts(void) +{ + R100(f400, 0); + R100(f400, 100); + R100(f400, 200); + R100(f400, 300); +} + +static void subtest_multispec_usdt(void) +{ + LIBBPF_OPTS(bpf_usdt_opts, opts); + struct test_usdt *skel; + struct test_usdt__bss *bss; + int err, i; + + skel = test_usdt__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bss = skel->bss; + bss->my_pid = getpid(); + + err = test_usdt__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* usdt_100 is auto-attached and there are 100 inlined call sites, + * let's validate that all of them are properly attached to and + * handled from BPF side + */ + trigger_100_usdts(); + + ASSERT_EQ(bss->usdt_100_called, 100, "usdt_100_called"); + ASSERT_EQ(bss->usdt_100_sum, 99 * 100 / 2, "usdt_100_sum"); + + /* Stress test free spec ID tracking. By default libbpf allows up to + * 256 specs to be used, so if we don't return free spec IDs back + * after few detachments and re-attachments we should run out of + * available spec IDs. + */ + for (i = 0; i < 2; i++) { + bpf_link__destroy(skel->links.usdt_100); + + skel->links.usdt_100 = bpf_program__attach_usdt(skel->progs.usdt_100, -1, + "/proc/self/exe", + "test", "usdt_100", NULL); + if (!ASSERT_OK_PTR(skel->links.usdt_100, "usdt_100_reattach")) + goto cleanup; + + bss->usdt_100_sum = 0; + trigger_100_usdts(); + + ASSERT_EQ(bss->usdt_100_called, (i + 1) * 100 + 100, "usdt_100_called"); + ASSERT_EQ(bss->usdt_100_sum, 99 * 100 / 2, "usdt_100_sum"); + } + + /* Now let's step it up and try to attach USDT that requires more than + * 256 attach points with different specs for each. + * Note that we need trigger_300_usdts() only to actually have 300 + * USDT call sites, we are not going to actually trace them. + */ + trigger_300_usdts(); + + /* we'll reuse usdt_100 BPF program for usdt_300 test */ + bpf_link__destroy(skel->links.usdt_100); + skel->links.usdt_100 = bpf_program__attach_usdt(skel->progs.usdt_100, -1, "/proc/self/exe", + "test", "usdt_300", NULL); + err = -errno; + if (!ASSERT_ERR_PTR(skel->links.usdt_100, "usdt_300_bad_attach")) + goto cleanup; + ASSERT_EQ(err, -E2BIG, "usdt_300_attach_err"); + + /* let's check that there are no "dangling" BPF programs attached due + * to partial success of the above test:usdt_300 attachment + */ + bss->usdt_100_called = 0; + bss->usdt_100_sum = 0; + + f300(777); /* this is 301st instance of usdt_300 */ + + ASSERT_EQ(bss->usdt_100_called, 0, "usdt_301_called"); + ASSERT_EQ(bss->usdt_100_sum, 0, "usdt_301_sum"); + + /* This time we have USDT with 400 inlined invocations, but arg specs + * should be the same across all sites, so libbpf will only need to + * use one spec and thus we'll be able to attach 400 uprobes + * successfully. + * + * Again, we are reusing usdt_100 BPF program. + */ + skel->links.usdt_100 = bpf_program__attach_usdt(skel->progs.usdt_100, -1, + "/proc/self/exe", + "test", "usdt_400", NULL); + if (!ASSERT_OK_PTR(skel->links.usdt_100, "usdt_400_attach")) + goto cleanup; + + trigger_400_usdts(); + + ASSERT_EQ(bss->usdt_100_called, 400, "usdt_400_called"); + ASSERT_EQ(bss->usdt_100_sum, 399 * 400 / 2, "usdt_400_sum"); + +cleanup: + test_usdt__destroy(skel); +} + +void test_usdt(void) +{ + if (test__start_subtest("basic")) + subtest_basic_usdt(); + if (test__start_subtest("multispec")) + subtest_multispec_usdt(); +} diff --git a/tools/testing/selftests/bpf/progs/test_usdt.c b/tools/testing/selftests/bpf/progs/test_usdt.c new file mode 100644 index 000000000000..cb800910d794 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_usdt.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include "vmlinux.h" +#include +#include + +int my_pid; + +int usdt0_called; +u64 usdt0_cookie; +int usdt0_arg_cnt; +int usdt0_arg_ret; + +SEC("usdt") +int usdt0(struct pt_regs *ctx) +{ + long tmp; + + if (my_pid != (bpf_get_current_pid_tgid() >> 32)) + return 0; + + __sync_fetch_and_add(&usdt0_called, 1); + + usdt0_cookie = bpf_usdt_cookie(ctx); + usdt0_arg_cnt = bpf_usdt_arg_cnt(ctx); + /* should return -ENOENT */ + usdt0_arg_ret = bpf_usdt_arg(ctx, 0, &tmp); + return 0; +} + +int usdt3_called; +u64 usdt3_cookie; +int usdt3_arg_cnt; +int usdt3_arg_rets[3]; +u64 usdt3_args[3]; + +SEC("usdt//proc/self/exe:test:usdt3") +int usdt3(struct pt_regs *ctx) +{ + long tmp; + + if (my_pid != (bpf_get_current_pid_tgid() >> 32)) + return 0; + + __sync_fetch_and_add(&usdt3_called, 1); + + usdt3_cookie = bpf_usdt_cookie(ctx); + usdt3_arg_cnt = bpf_usdt_arg_cnt(ctx); + + usdt3_arg_rets[0] = bpf_usdt_arg(ctx, 0, &tmp); + usdt3_args[0] = (int)tmp; + + usdt3_arg_rets[1] = bpf_usdt_arg(ctx, 1, &tmp); + usdt3_args[1] = (long)tmp; + + usdt3_arg_rets[2] = bpf_usdt_arg(ctx, 2, &tmp); + usdt3_args[2] = (uintptr_t)tmp; + + return 0; +} + +int usdt12_called; +u64 usdt12_cookie; +int usdt12_arg_cnt; +u64 usdt12_args[12]; + +SEC("usdt//proc/self/exe:test:usdt12") +int BPF_USDT(usdt12, int a1, int a2, long a3, long a4, unsigned a5, + long a6, __u64 a7, uintptr_t a8, int a9, short a10, + short a11, signed char a12) +{ + if (my_pid != (bpf_get_current_pid_tgid() >> 32)) + return 0; + + __sync_fetch_and_add(&usdt12_called, 1); + + usdt12_cookie = bpf_usdt_cookie(ctx); + usdt12_arg_cnt = bpf_usdt_arg_cnt(ctx); + + usdt12_args[0] = a1; + usdt12_args[1] = a2; + usdt12_args[2] = a3; + usdt12_args[3] = a4; + usdt12_args[4] = a5; + usdt12_args[5] = a6; + usdt12_args[6] = a7; + usdt12_args[7] = a8; + usdt12_args[8] = a9; + usdt12_args[9] = a10; + usdt12_args[10] = a11; + usdt12_args[11] = a12; + return 0; +} + +int usdt_100_called; +int usdt_100_sum; + +SEC("usdt//proc/self/exe:test:usdt_100") +int BPF_USDT(usdt_100, int x) +{ + long tmp; + + if (my_pid != (bpf_get_current_pid_tgid() >> 32)) + return 0; + + __sync_fetch_and_add(&usdt_100_called, 1); + __sync_fetch_and_add(&usdt_100_sum, x); + + bpf_printk("X is %d, sum is %d", x, usdt_100_sum); + + return 0; +} + +char _license[] SEC("license") = "GPL"; -- 2.30.2