From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 982374C81; Sat, 6 Jun 2026 12:43:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780749793; cv=none; b=R7L6JhB2hxg1VFlSS07uTKOAmwhSGmFUfHYcyZkqMUhdWCTsB0bszELvql48/fJCo30vXvN+eTP/ORPslhV3B5PtIeVDD0tH2/c59b22S4ph7HXmFEVd4Bc2p3mWdCGVlR/F/tWQH+Jab9e3I67XmPAag+FK9ugP6VFYPNCxh8Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780749793; c=relaxed/simple; bh=0espHjd5KuqOkBi6Z6xKeVsQuEa3EPPcP8Op0oBTT70=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=knLswCOaWZ4VkcotXJo5O3mQdSeEQs45wguc+RKIHzQMPdkLSNF1Fn99zM/n2mKar7MkleXFIcp2/QMCIJyBTIg9KmgUyBpGQhx/pcX06+VZY5QBrWuJrrkUctjRZvN5PYh+yHoJd5PVLZrD+iEMSnhw1adX5M3hkyEqlMFlvhk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kyNfIP/r; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kyNfIP/r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76C741F00893; Sat, 6 Jun 2026 12:43:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780749792; bh=LpC1VfdpmhyFJqCWppxN01ffuh69bj8R8Nk+SqJP5lw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kyNfIP/rxxID7GA/OI7a9nHdjfHIE+sGsrBrgf7v25H3PKwtWVaUmCqXbp8AdF8XV 1S4JiSL21ptG1pflULKF3nxYRghaPf6c9QMo1NMQ247WcVsedGfDYXi2HBO2CoVY2h gZwMFzU2h/YMjtMVHnQDoUaCaC4LV6ZE+3GGM485sb9x/L55EzFLPJRSbngRtvKnL3 nj5JjkAHdyKadEpxUfhK9F3gHE8XJI3qrkrsiLiDdgicJh+uNHOWsm4gt7sM5iUToB 2Wev/jBb+ArAw5MFBrhF/YLYaUxxVelqyME4BEctEDMGyfWB9NhQqU86pzqmxo9DKm yy0KwKNAx0UeA== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , Menglong Dong , Steven Rostedt Subject: [PATCHv8 bpf-next 19/29] libbpf: Add btf_type_is_traceable_func function Date: Sat, 6 Jun 2026 14:39:44 +0200 Message-ID: <20260606123955.345967-20-jolsa@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260606123955.345967-1-jolsa@kernel.org> References: <20260606123955.345967-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Adding btf_type_is_traceable_func function to perform same checks as the kernel's btf_distill_func_proto function to prevent attachment on some of the functions. Exporting the function via libbpf_internal.h because it will be used by benchmark test in following changes. Signed-off-by: Jiri Olsa --- tools/lib/bpf/libbpf.c | 79 +++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf_internal.h | 1 + 2 files changed, 80 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5bdaa5eb1f50..42f0efd70327 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -12450,6 +12450,85 @@ static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, stru return ret; } +#define MAX_BPF_FUNC_ARGS 12 + +static bool btf_type_is_modifier(const struct btf_type *t) +{ + switch (BTF_INFO_KIND(t->info)) { + case BTF_KIND_TYPEDEF: + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_TYPE_TAG: + return true; + default: + return false; + } +} + +#define MAX_RESOLVE_DEPTH 32 + +static int btf_get_type_size(const struct btf *btf, __u32 type_id, + const struct btf_type **ret_type) +{ + const struct btf_type *t; + int i; + + *ret_type = btf__type_by_id(btf, 0); + if (!type_id) + return 0; + t = btf__type_by_id(btf, type_id); + for (i = 0; i < MAX_RESOLVE_DEPTH && t && btf_type_is_modifier(t); i++) + t = btf__type_by_id(btf, t->type); + if (!t || i == MAX_RESOLVE_DEPTH) + return -EINVAL; + *ret_type = t; + if (btf_is_ptr(t)) + return btf__pointer_size(btf); + if (btf_is_int(t) || btf_is_any_enum(t) || btf_is_struct(t) || btf_is_union(t)) + return t->size; + return -EINVAL; +} + +bool btf_type_is_traceable_func(const struct btf *btf, const struct btf_type *t) +{ + const struct btf_param *args; + const struct btf_type *proto; + __u32 i, nargs; + int ret; + + if (!btf_is_func(t)) + return false; + proto = btf__type_by_id(btf, t->type); + if (!proto || !btf_is_func_proto(proto)) + return false; + + args = (const struct btf_param *)(proto + 1); + nargs = btf_vlen(proto); + if (nargs > MAX_BPF_FUNC_ARGS) + return false; + + /* No support for struct return type. */ + ret = btf_get_type_size(btf, proto->type, &t); + if (ret < 0 || btf_is_struct(t) || btf_is_union(t)) + return false; + + for (i = 0; i < nargs; i++) { + /* No support for variable args. */ + if (i == nargs - 1 && args[i].type == 0) + return false; + ret = btf_get_type_size(btf, args[i].type, &t); + /* No support of struct argument size greater than 16 bytes. */ + if (ret < 0 || ret > 16) + return false; + /* No support for void argument. */ + if (ret == 0) + return false; + } + + return true; +} + static inline int add_uprobe_event_legacy(const char *probe_name, bool retprobe, const char *binary_path, size_t offset) { diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 7d93c6c01d60..04cd303fb5a8 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -250,6 +250,7 @@ const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, _ const struct btf_header *btf_header(const struct btf *btf); void btf_set_base_btf(struct btf *btf, const struct btf *base_btf); int btf_relocate(struct btf *btf, const struct btf *base_btf, __u32 **id_map); +bool btf_type_is_traceable_func(const struct btf *btf, const struct btf_type *t); static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) { -- 2.54.0