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 X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33549C433EF for ; Tue, 7 Sep 2021 20:28:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E8BA6115C for ; Tue, 7 Sep 2021 20:28:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346658AbhIGUaB (ORCPT ); Tue, 7 Sep 2021 16:30:01 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:32654 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1346520AbhIGU3s (ORCPT ); Tue, 7 Sep 2021 16:29:48 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.43/8.16.0.43) with SMTP id 187KRFiI003795 for ; Tue, 7 Sep 2021 13:28:41 -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-transfer-encoding : content-type; s=facebook; bh=evZMmfU690epbmaRHFUfjC1IXQGgSDnM9C8Ch86lkRc=; b=AIDzIy37tjmJY01XL2555fraDs5TuEhOkKOjH9XzsD7m/6AD7OD5VpzXwfl+l7oy61p0 NcUrwm7PZXAebxOP/b70cFB6IjjiYf6IHguBU7veNrREeQJFHm8QtqsDez1WW2EiItxC Ug8ePGST4uqQKFa4rVZ+UYPVoLE31Dhr3C4= Received: from mail.thefacebook.com ([163.114.132.120]) by m0001303.ppops.net with ESMTP id 3axcnxs7gk-20 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 07 Sep 2021 13:28:41 -0700 Received: from intmgw001.25.frc3.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.14; Tue, 7 Sep 2021 13:28:36 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 31C671027A65E; Tue, 7 Sep 2021 13:28:36 -0700 (PDT) From: Song Liu To: , CC: , , , , , Song Liu , Andrii Nakryiko , John Fastabend Subject: [PATCH v6 bpf-next 3/3] selftests/bpf: add test for bpf_get_branch_snapshot Date: Tue, 7 Sep 2021 13:28:02 -0700 Message-ID: <20210907202802.3675104-4-songliubraving@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210907202802.3675104-1-songliubraving@fb.com> References: <20210907202802.3675104-1-songliubraving@fb.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-FB-Source: Intern X-Proofpoint-GUID: up6iXsdjmaoeAl6p4fd-aKkLW3DJb2qE X-Proofpoint-ORIG-GUID: up6iXsdjmaoeAl6p4fd-aKkLW3DJb2qE X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-09-07_07:2021-09-07,2021-09-07 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 suspectscore=0 phishscore=0 mlxlogscore=999 priorityscore=1501 bulkscore=0 adultscore=0 impostorscore=0 lowpriorityscore=0 spamscore=0 clxscore=1015 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109070130 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This test uses bpf_get_branch_snapshot from a fexit program. The test use= s a target function (bpf_testmod_loop_test) and compares the record against kallsyms. If there isn't enough record matching kallsyms, the test fails. Acked-by: Andrii Nakryiko Acked-by: John Fastabend Signed-off-by: Song Liu --- .../selftests/bpf/bpf_testmod/bpf_testmod.c | 19 +++- .../selftests/bpf/prog_tests/core_reloc.c | 14 +-- .../bpf/prog_tests/get_branch_snapshot.c | 100 ++++++++++++++++++ .../selftests/bpf/prog_tests/module_attach.c | 39 ------- .../selftests/bpf/progs/get_branch_snapshot.c | 40 +++++++ tools/testing/selftests/bpf/test_progs.c | 39 +++++++ tools/testing/selftests/bpf/test_progs.h | 2 + tools/testing/selftests/bpf/trace_helpers.c | 37 +++++++ tools/testing/selftests/bpf/trace_helpers.h | 5 + 9 files changed, 243 insertions(+), 52 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/get_branch_sna= pshot.c create mode 100644 tools/testing/selftests/bpf/progs/get_branch_snapshot= .c diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tool= s/testing/selftests/bpf/bpf_testmod/bpf_testmod.c index 141d8da687d21..50fc5561110a4 100644 --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c @@ -13,6 +13,18 @@ =20 DEFINE_PER_CPU(int, bpf_testmod_ksym_percpu) =3D 123; =20 +noinline int bpf_testmod_loop_test(int n) +{ + int i, sum =3D 0; + + /* the primary goal of this test is to test LBR. Create a lot of + * branches in the function, so we can catch it easily. + */ + for (i =3D 0; i < n; i++) + sum +=3D i; + return sum; +} + noinline ssize_t bpf_testmod_test_read(struct file *file, struct kobject *kobj, struct bin_attribute *bin_attr, @@ -24,7 +36,11 @@ bpf_testmod_test_read(struct file *file, struct kobjec= t *kobj, .len =3D len, }; =20 - trace_bpf_testmod_test_read(current, &ctx); + /* This is always true. Use the check to make sure the compiler + * doesn't remove bpf_testmod_loop_test. + */ + if (bpf_testmod_loop_test(101) > 100) + trace_bpf_testmod_test_read(current, &ctx); =20 return -EIO; /* always fail */ } @@ -71,4 +87,3 @@ module_exit(bpf_testmod_exit); MODULE_AUTHOR("Andrii Nakryiko"); MODULE_DESCRIPTION("BPF selftests module"); MODULE_LICENSE("Dual BSD/GPL"); - diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/= testing/selftests/bpf/prog_tests/core_reloc.c index 4739b15b2a979..15d355af8d1d2 100644 --- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c +++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c @@ -30,7 +30,7 @@ static int duration =3D 0; .output_len =3D sizeof(struct core_reloc_module_output), \ .prog_sec_name =3D sec_name, \ .raw_tp_name =3D tp_name, \ - .trigger =3D trigger_module_test_read, \ + .trigger =3D __trigger_module_test_read, \ .needs_testmod =3D true, \ } =20 @@ -475,19 +475,11 @@ static int setup_type_id_case_failure(struct core_r= eloc_test_case *test) return 0; } =20 -static int trigger_module_test_read(const struct core_reloc_test_case *t= est) +static int __trigger_module_test_read(const struct core_reloc_test_case = *test) { struct core_reloc_module_output *exp =3D (void *)test->output; - int fd, err; - - fd =3D open("/sys/kernel/bpf_testmod", O_RDONLY); - err =3D -errno; - if (CHECK(fd < 0, "testmod_file_open", "failed: %d\n", err)) - return err; - - read(fd, NULL, exp->len); /* request expected number of bytes */ - close(fd); =20 + trigger_module_test_read(exp->len); return 0; } =20 diff --git a/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c= b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c new file mode 100644 index 0000000000000..26af9b3d572e3 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include +#include "get_branch_snapshot.skel.h" + +static int *pfd_array; +static int cpu_cnt; + +static int create_perf_events(void) +{ + struct perf_event_attr attr =3D {0}; + int cpu; + + /* create perf event */ + attr.size =3D sizeof(attr); + attr.type =3D PERF_TYPE_RAW; + attr.config =3D 0x1b00; + attr.sample_type =3D PERF_SAMPLE_BRANCH_STACK; + attr.branch_sample_type =3D PERF_SAMPLE_BRANCH_KERNEL | + PERF_SAMPLE_BRANCH_USER | PERF_SAMPLE_BRANCH_ANY; + + cpu_cnt =3D libbpf_num_possible_cpus(); + pfd_array =3D malloc(sizeof(int) * cpu_cnt); + if (!pfd_array) { + cpu_cnt =3D 0; + return 1; + } + + for (cpu =3D 0; cpu < cpu_cnt; cpu++) { + pfd_array[cpu] =3D syscall(__NR_perf_event_open, &attr, + -1, cpu, -1, PERF_FLAG_FD_CLOEXEC); + if (pfd_array[cpu] < 0) + break; + } + + return cpu =3D=3D 0; +} + +static void close_perf_events(void) +{ + int cpu =3D 0; + int fd; + + while (cpu++ < cpu_cnt) { + fd =3D pfd_array[cpu]; + if (fd < 0) + break; + close(fd); + } + free(pfd_array); +} + +void test_get_branch_snapshot(void) +{ + struct get_branch_snapshot *skel =3D NULL; + int err; + + if (create_perf_events()) { + test__skip(); /* system doesn't support LBR */ + goto cleanup; + } + + skel =3D get_branch_snapshot__open_and_load(); + if (!ASSERT_OK_PTR(skel, "get_branch_snapshot__open_and_load")) + goto cleanup; + + err =3D kallsyms_find("bpf_testmod_loop_test", &skel->bss->address_low)= ; + if (!ASSERT_OK(err, "kallsyms_find")) + goto cleanup; + + err =3D kallsyms_find_next("bpf_testmod_loop_test", &skel->bss->address= _high); + if (!ASSERT_OK(err, "kallsyms_find_next")) + goto cleanup; + + err =3D get_branch_snapshot__attach(skel); + if (!ASSERT_OK(err, "get_branch_snapshot__attach")) + goto cleanup; + + trigger_module_test_read(100); + + if (skel->bss->total_entries < 16) { + /* too few entries for the hit/waste test */ + test__skip(); + goto cleanup; + } + + ASSERT_GT(skel->bss->test1_hits, 1, "find_looptest_in_lbr"); + + /* Given we stop LBR in software, we will waste a few entries. + * But we should try to waste as few as possible entries. We are at + * about 11 on x86_64 systems. + * Add a check for < 15 so that we get heads-up when something + * changes and wastes too many entries. + */ + ASSERT_LT(skel->bss->wasted_entries, 15, "check_wasted_entries"); + +cleanup: + get_branch_snapshot__destroy(skel); + close_perf_events(); +} diff --git a/tools/testing/selftests/bpf/prog_tests/module_attach.c b/too= ls/testing/selftests/bpf/prog_tests/module_attach.c index d85a69b7ce449..1797a6e4d6d84 100644 --- a/tools/testing/selftests/bpf/prog_tests/module_attach.c +++ b/tools/testing/selftests/bpf/prog_tests/module_attach.c @@ -6,45 +6,6 @@ =20 static int duration; =20 -static int trigger_module_test_read(int read_sz) -{ - int fd, err; - - fd =3D open("/sys/kernel/bpf_testmod", O_RDONLY); - err =3D -errno; - if (CHECK(fd < 0, "testmod_file_open", "failed: %d\n", err)) - return err; - - read(fd, NULL, read_sz); - close(fd); - - return 0; -} - -static int trigger_module_test_write(int write_sz) -{ - int fd, err; - char *buf =3D malloc(write_sz); - - if (!buf) - return -ENOMEM; - - memset(buf, 'a', write_sz); - buf[write_sz-1] =3D '\0'; - - fd =3D open("/sys/kernel/bpf_testmod", O_WRONLY); - err =3D -errno; - if (CHECK(fd < 0, "testmod_file_open", "failed: %d\n", err)) { - free(buf); - return err; - } - - write(fd, buf, write_sz); - close(fd); - free(buf); - return 0; -} - static int delete_module(const char *name, int flags) { return syscall(__NR_delete_module, name, flags); diff --git a/tools/testing/selftests/bpf/progs/get_branch_snapshot.c b/to= ols/testing/selftests/bpf/progs/get_branch_snapshot.c new file mode 100644 index 0000000000000..a1b139888048c --- /dev/null +++ b/tools/testing/selftests/bpf/progs/get_branch_snapshot.c @@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") =3D "GPL"; + +__u64 test1_hits =3D 0; +__u64 address_low =3D 0; +__u64 address_high =3D 0; +int wasted_entries =3D 0; +long total_entries =3D 0; + +#define ENTRY_CNT 32 +struct perf_branch_entry entries[ENTRY_CNT] =3D {}; + +static inline bool in_range(__u64 val) +{ + return (val >=3D address_low) && (val < address_high); +} + +SEC("fexit/bpf_testmod_loop_test") +int BPF_PROG(test1, int n, int ret) +{ + long i; + + total_entries =3D bpf_get_branch_snapshot(entries, sizeof(entries), 0); + total_entries /=3D sizeof(struct perf_branch_entry); + + for (i =3D 0; i < ENTRY_CNT; i++) { + if (i >=3D total_entries) + break; + if (in_range(entries[i].from) && in_range(entries[i].to)) + test1_hits++; + else if (!test1_hits) + wasted_entries++; + } + return 0; +} diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/sel= ftests/bpf/test_progs.c index cc1cd240445d2..2ed01f615d20f 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -743,6 +743,45 @@ int cd_flavor_subdir(const char *exec_name) return chdir(flavor); } =20 +int trigger_module_test_read(int read_sz) +{ + int fd, err; + + fd =3D open("/sys/kernel/bpf_testmod", O_RDONLY); + err =3D -errno; + if (!ASSERT_GE(fd, 0, "testmod_file_open")) + return err; + + read(fd, NULL, read_sz); + close(fd); + + return 0; +} + +int trigger_module_test_write(int write_sz) +{ + int fd, err; + char *buf =3D malloc(write_sz); + + if (!buf) + return -ENOMEM; + + memset(buf, 'a', write_sz); + buf[write_sz-1] =3D '\0'; + + fd =3D open("/sys/kernel/bpf_testmod", O_WRONLY); + err =3D -errno; + if (!ASSERT_GE(fd, 0, "testmod_file_open")) { + free(buf); + return err; + } + + write(fd, buf, write_sz); + close(fd); + free(buf); + return 0; +} + #define MAX_BACKTRACE_SZ 128 void crash_handler(int signum) { diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/sel= ftests/bpf/test_progs.h index c8c2bf878f67c..94bef0aa74cf5 100644 --- a/tools/testing/selftests/bpf/test_progs.h +++ b/tools/testing/selftests/bpf/test_progs.h @@ -291,6 +291,8 @@ int compare_map_keys(int map1_fd, int map2_fd); int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len); int extract_build_id(char *build_id, size_t size); int kern_sync_rcu(void); +int trigger_module_test_read(int read_sz); +int trigger_module_test_write(int write_sz); =20 #ifdef __x86_64__ #define SYS_NANOSLEEP_KPROBE_NAME "__x64_sys_nanosleep" diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/= selftests/bpf/trace_helpers.c index e7a19b04d4eaf..5100a169b72b1 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -1,4 +1,5 @@ // SPDX-License-Identifier: GPL-2.0 +#include #include #include #include @@ -117,6 +118,42 @@ int kallsyms_find(const char *sym, unsigned long lon= g *addr) return err; } =20 +/* find the address of the next symbol of the same type, this can be use= d + * to determine the end of a function. + */ +int kallsyms_find_next(const char *sym, unsigned long long *addr) +{ + char type, found_type, name[500]; + unsigned long long value; + bool found =3D false; + int err =3D 0; + FILE *f; + + f =3D fopen("/proc/kallsyms", "r"); + if (!f) + return -EINVAL; + + while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) { + /* Different types of symbols in kernel modules are mixed + * in /proc/kallsyms. Only return the next matching type. + * Use tolower() for type so that 'T' matches 't'. + */ + if (found && found_type =3D=3D tolower(type)) { + *addr =3D value; + goto out; + } + if (strcmp(name, sym) =3D=3D 0) { + found =3D true; + found_type =3D tolower(type); + } + } + err =3D -ENOENT; + +out: + fclose(f); + return err; +} + void read_trace_pipe(void) { int trace_fd; diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/= selftests/bpf/trace_helpers.h index d907b445524d5..bc8ed86105d94 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -16,6 +16,11 @@ long ksym_get_addr(const char *name); /* open kallsyms and find addresses on the fly, faster than load + searc= h. */ int kallsyms_find(const char *sym, unsigned long long *addr); =20 +/* find the address of the next symbol, this can be used to determine th= e + * end of a function + */ +int kallsyms_find_next(const char *sym, unsigned long long *addr); + void read_trace_pipe(void); =20 ssize_t get_uprobe_offset(const void *addr, ssize_t base); --=20 2.30.2