[bpf-next,v2,8/9] libbpf: add support for the multi-link of tracing

Message ID	20240311093526.1010158-9-dongmenglong.8@bytedance.com (mailing list archive)
State	New
Headers	show Received: from mail-pl1-f178.google.com (mail-pl1-f178.google.com [209.85.214.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 01E203DBA1 for <linux-kselftest@vger.kernel.org>; Mon, 11 Mar 2024 09:35:31 +0000 (UTC) From: Menglong Dong <dongmenglong.8@bytedance.com> To: andrii@kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, davem@davemloft.net, dsahern@kernel.org, dave.hansen@linux.intel.com, x86@kernel.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, quentin@isovalent.com, bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, Menglong Dong <dongmenglong.8@bytedance.com> Subject: [PATCH bpf-next v2 8/9] libbpf: add support for the multi-link of tracing Date: Mon, 11 Mar 2024 17:35:25 +0800 Message-Id: <20240311093526.1010158-9-dongmenglong.8@bytedance.com> In-Reply-To: <20240311093526.1010158-1-dongmenglong.8@bytedance.com> References: <20240311093526.1010158-1-dongmenglong.8@bytedance.com> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	bpf: make tracing program support multi-link \| expand [bpf-next,v2,0/9] bpf: make tracing program support multi-link [bpf-next,v2,1/9] bpf: tracing: add support to record and check the accessed args [bpf-next,v2,2/9] bpf: refactor the modules_array to ptr_array [bpf-next,v2,3/9] bpf: trampoline: introduce struct bpf_tramp_link_conn [bpf-next,v2,4/9] bpf: trampoline: introduce bpf_tramp_multi_link [bpf-next,v2,5/9] bpf: verifier: add btf to the function args of bpf_check_attach_target [bpf-next,v2,6/9] bpf: tracing: add multi-link support [bpf-next,v2,7/9] libbpf: don't free btf if program of multi-link tracing existing [bpf-next,v2,8/9] libbpf: add support for the multi-link of tracing [bpf-next,v2,9/9] selftests/bpf: add testcases for multi-link of tracing

diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index cc6e6aae2447..ffc85256671d 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -1089,6 +1089,9 @@ const char *bpf_attach_type_input_str(enum bpf_attach_type t) case BPF_TRACE_FENTRY: return "fentry"; case BPF_TRACE_FEXIT: return "fexit"; case BPF_MODIFY_RETURN: return "mod_ret"; + case BPF_TRACE_FENTRY_MULTI: return "fentry_multi"; + case BPF_TRACE_FEXIT_MULTI: return "fexit_multi"; + case BPF_MODIFY_RETURN_MULTI: return "mod_ret_multi"; case BPF_SK_REUSEPORT_SELECT: return "sk_skb_reuseport_select"; case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE: return "sk_skb_reuseport_select_or_migrate"; default: return libbpf_bpf_attach_type_str(t); diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 97ec005c3c47..63d4734dbae4 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -793,6 +793,16 @@ int bpf_link_create(int prog_fd, int target_fd, if (!OPTS_ZEROED(opts, tracing)) return libbpf_err(-EINVAL); break; + case BPF_TRACE_FENTRY_MULTI: + case BPF_TRACE_FEXIT_MULTI: + case BPF_MODIFY_RETURN_MULTI: + attr.link_create.tracing_multi.btf_ids = ptr_to_u64(OPTS_GET(opts, tracing_multi.btf_ids, 0)); + attr.link_create.tracing_multi.tgt_fds = ptr_to_u64(OPTS_GET(opts, tracing_multi.tgt_fds, 0)); + attr.link_create.tracing_multi.cookies = ptr_to_u64(OPTS_GET(opts, tracing_multi.cookies, 0)); + attr.link_create.tracing_multi.cnt = OPTS_GET(opts, tracing_multi.cnt, 0); + if (!OPTS_ZEROED(opts, tracing_multi)) + return libbpf_err(-EINVAL); + break; case BPF_NETFILTER: attr.link_create.netfilter.pf = OPTS_GET(opts, netfilter.pf, 0); attr.link_create.netfilter.hooknum = OPTS_GET(opts, netfilter.hooknum, 0); diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index df0db2f0cdb7..e28c88d6cfa4 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -419,6 +419,12 @@ struct bpf_link_create_opts { struct { __u64 cookie; } tracing; + struct { + __u32 cnt; + const __u32 *btf_ids; + const __u32 *tgt_fds; + const __u64 *cookies; + } tracing_multi; struct { __u32 pf; __u32 hooknum; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index fd5428494a7e..821214774941 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -132,6 +132,9 @@ static const char * const attach_type_name[] = { [BPF_TRACE_UPROBE_MULTI] = "trace_uprobe_multi", [BPF_NETKIT_PRIMARY] = "netkit_primary", [BPF_NETKIT_PEER] = "netkit_peer", + [BPF_TRACE_FENTRY_MULTI] = "trace_fentry_multi", + [BPF_TRACE_FEXIT_MULTI] = "trace_fexit_multi", + [BPF_MODIFY_RETURN_MULTI] = "modify_return_multi", }; static const char * const link_type_name[] = { @@ -381,6 +384,8 @@ enum sec_def_flags { SEC_XDP_FRAGS = 16, /* Setup proper attach type for usdt probes. */ SEC_USDT = 32, + /* attachment target is multi-link */ + SEC_ATTACH_BTF_MULTI = 64, }; struct bpf_sec_def { @@ -7160,9 +7165,9 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog, if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI; - if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { + if ((def & (SEC_ATTACH_BTF | SEC_ATTACH_BTF_MULTI)) && !prog->attach_btf_id) { int btf_obj_fd = 0, btf_type_id = 0, err; - const char *attach_name; + const char *attach_name, *name_end; attach_name = strchr(prog->sec_name, '/'); if (!attach_name) { @@ -7181,7 +7186,27 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog, } attach_name++; /* skip over / */ - err = libbpf_find_attach_btf_id(prog, attach_name, &btf_obj_fd, &btf_type_id); + name_end = strchr(attach_name, ','); + /* for multi-link tracing, use the first target symbol during + * loading. + */ + if ((def & SEC_ATTACH_BTF_MULTI) && name_end) { + int len = name_end - attach_name + 1; + char *first_tgt; + + first_tgt = malloc(len); + if (!first_tgt) + return -ENOMEM; + strncpy(first_tgt, attach_name, len); + first_tgt[len - 1] = '\0'; + err = libbpf_find_attach_btf_id(prog, first_tgt, &btf_obj_fd, + &btf_type_id); + free(first_tgt); + } else { + err = libbpf_find_attach_btf_id(prog, attach_name, &btf_obj_fd, + &btf_type_id); + } + if (err) return err; @@ -9149,6 +9174,7 @@ static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, stru static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link); static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link); +static int attach_trace_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link); static const struct bpf_sec_def section_defs[] = { SEC_DEF("socket", SOCKET_FILTER, 0, SEC_NONE), @@ -9192,6 +9218,13 @@ static const struct bpf_sec_def section_defs[] = { SEC_DEF("fentry.s+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), SEC_DEF("fmod_ret.s+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), SEC_DEF("fexit.s+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace), + SEC_DEF("tp_btf+", TRACING, BPF_TRACE_RAW_TP, SEC_ATTACH_BTF, attach_trace), + SEC_DEF("fentry.multi+", TRACING, BPF_TRACE_FENTRY_MULTI, SEC_ATTACH_BTF_MULTI, attach_trace_multi), + SEC_DEF("fmod_ret.multi+", TRACING, BPF_MODIFY_RETURN_MULTI, SEC_ATTACH_BTF_MULTI, attach_trace_multi), + SEC_DEF("fexit.multi+", TRACING, BPF_TRACE_FEXIT_MULTI, SEC_ATTACH_BTF_MULTI, attach_trace_multi), + SEC_DEF("fentry.multi.s+", TRACING, BPF_TRACE_FENTRY_MULTI, SEC_ATTACH_BTF_MULTI | SEC_SLEEPABLE, attach_trace_multi), + SEC_DEF("fmod_ret.multi.s+", TRACING, BPF_MODIFY_RETURN_MULTI, SEC_ATTACH_BTF_MULTI | SEC_SLEEPABLE, attach_trace_multi), + SEC_DEF("fexit.multi.s+", TRACING, BPF_TRACE_FEXIT_MULTI, SEC_ATTACH_BTF_MULTI | SEC_SLEEPABLE, attach_trace_multi), SEC_DEF("freplace+", EXT, 0, SEC_ATTACH_BTF, attach_trace), SEC_DEF("lsm+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm), SEC_DEF("lsm.s+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm), @@ -12300,6 +12333,135 @@ static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_ return libbpf_get_error(*link); } +struct bpf_link *bpf_program__attach_trace_multi_opts(const struct bpf_program *prog, + const struct bpf_trace_multi_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, link_opts); + __u32 *btf_ids = NULL, *tgt_fds = NULL; + struct bpf_link *link = NULL; + char errmsg[STRERR_BUFSIZE]; + int prog_fd, pfd, cnt, err; + + if (!OPTS_VALID(opts, bpf_trace_multi_opts)) + return libbpf_err_ptr(-EINVAL); + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return libbpf_err_ptr(-EINVAL); + } + + cnt = OPTS_GET(opts, cnt, 0); + if (opts->syms) { + int btf_obj_fd, btf_type_id, i; + + if (opts->btf_ids || opts->tgt_fds) { + pr_warn("can set both opts->syms and opts->btf_ids\n"); + return libbpf_err_ptr(-EINVAL); + } + + btf_ids = malloc(sizeof(*btf_ids) * cnt); + tgt_fds = malloc(sizeof(*tgt_fds) * cnt); + if (!btf_ids || !tgt_fds) { + err = -ENOMEM; + goto err_free; + } + for (i = 0; i < cnt; i++) { + btf_obj_fd = btf_type_id = 0; + + err = find_kernel_btf_id(prog->obj, opts->syms[i], + prog->expected_attach_type, &btf_obj_fd, + &btf_type_id); + if (err) + goto err_free; + btf_ids[i] = btf_type_id; + tgt_fds[i] = btf_obj_fd; + } + link_opts.tracing_multi.btf_ids = btf_ids; + link_opts.tracing_multi.tgt_fds = tgt_fds; + } else { + link_opts.tracing_multi.btf_ids = OPTS_GET(opts, btf_ids, 0); + link_opts.tracing_multi.tgt_fds = OPTS_GET(opts, tgt_fds, 0); + } + + link = calloc(1, sizeof(*link)); + if (!link) { + err = -ENOMEM; + goto err_free; + } + link->detach = &bpf_link__detach_fd; + + link_opts.tracing_multi.cookies = OPTS_GET(opts, cookies, 0); + link_opts.tracing_multi.cnt = cnt; + + pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), &link_opts); + if (pfd < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach: %s\n", + prog->name, libbpf_strerror_r(pfd, errmsg, sizeof(errmsg))); + goto err_free; + } + link->fd = pfd; + + free(btf_ids); + free(tgt_fds); + return link; +err_free: + free(btf_ids); + free(tgt_fds); + free(link); + return libbpf_err_ptr(err); +} + +static int attach_trace_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link) +{ + LIBBPF_OPTS(bpf_trace_multi_opts, opts); + int i, err, len, cnt = 1; + char **syms, *buf, *name; + const char *spec; + + spec = strchr(prog->sec_name, '/'); + if (!spec || !*(++spec)) + return -EINVAL; + + len = strlen(spec); + buf = malloc(len + 1); + if (!buf) + return -ENOMEM; + + strcpy(buf, spec); + for (i = 0; i < len; i++) { + if (buf[i] == ',') + cnt++; + } + + syms = malloc(sizeof(*syms) * cnt); + if (!syms) { + err = -ENOMEM; + goto out_free; + } + + opts.syms = (const char **)syms; + opts.cnt = cnt; + name = buf; + err = -EINVAL; + while (name) { + if (*name == '\0') + goto out_free; + *(syms++) = name; + name = strchr(name, ','); + if (name) + *(name++) = '\0'; + } + + *link = bpf_program__attach_trace_multi_opts(prog, &opts); + err = libbpf_get_error(*link); +out_free: + free(buf); + free(opts.syms); + return err; +} + static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link) { *link = bpf_program__attach_lsm(prog); diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index c41a909ea4c1..9bca44d5adfa 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -790,6 +790,20 @@ bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex); LIBBPF_API struct bpf_link * bpf_program__attach_freplace(const struct bpf_program *prog, int target_fd, const char *attach_func_name); +struct bpf_trace_multi_opts { + /* size of this struct, for forward/backward compatibility */ + size_t sz; + const char **syms; + __u32 *btf_ids; + __u32 *tgt_fds; + __u64 *cookies; + size_t cnt; +}; +#define bpf_trace_multi_opts__last_field cnt + +LIBBPF_API struct bpf_link * +bpf_program__attach_trace_multi_opts(const struct bpf_program *prog, + const struct bpf_trace_multi_opts *opts); struct bpf_netfilter_opts { /* size of this struct, for forward/backward compatibility */ diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 57642b78917f..94933898df44 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -414,4 +414,5 @@ LIBBPF_1.4.0 { btf__new_split; btf_ext__raw_data; bpf_object__free_btfs; + bpf_program__attach_trace_multi_opts; } LIBBPF_1.3.0;

[bpf-next,v2,8/9] libbpf: add support for the multi-link of tracing

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