From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.216.45 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792437955; b=hJJt96y/Jh7bY+XLOlibgj769/0Of/vHLsHrMFUrf5NbxNHGjKLY1aRVagDtM3bFZFzE Gk7Tq16wtntuTCASdomlto6bVmZfT7Wkop3Vx849jgRG5AzG8V803YrHXPIjeY+4QntBw v/xH3LVl89u1v7O6gwqXGiyLEvGNA5O+vdQ10PDebABqbVCUwaZPzKWXb+en45JjFw1k+ zsHtdyhFmuhteeJeV02/N5UQGQewbii6ugkCXX2zx4Xev/m0kdOV3FXQneLtUPCZ+KtUs TjL+gacF8/rzz/qkMm/gMwJc6XkpC/hGGrFv2g+bGT3IcG9DLg41kUUrx6jJ5FlAIzQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792437955; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: Content-Type:Date:Message-Id:Cc:Subject:From:To:In-Reply-To: References:X-Mailer:Content-Transfer-Encoding:MIME-Version; bh=Gl+QuejblNFV3uEkIxOgOsS4jX0GlJs/ROUNx5zrPn4=; b=XUwTmHJDgWuKa9bqa5+r3n4/OblJhCS8rY/A03k+psEl8SC+Zze5vhNTW0NciyY1RTve 9FfDh9l2OHeZgHlUXLCQXXKPFDCOW6eO6GYbQlp2QUHlRm2sWCApGQRLx4W9EJpPvxXgR ju9L5CsAjRQKXGvrGOAhaw6xHFNWbXo+4Zh5cgrcA9b6UbaS8Sg38IZIGJcnQUmPoZccZ pGbXLgx4f9TrxZwV8Z9GUYUIKOOcLsOws/4eI3rdBh6Pa1YYBeyksgyYOp03TgljIohQG KrBPlMiv5odQR5b634OxhLCsmqALTNsIpQZPok0CXjLUTqvSEJ1qJ792MFECdZsYrtQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=gYnQr9al; arc=none smtp.remote-ip=209.85.216.45 Received: from mail-pj1-f45.google.com (mail-pj1-f45.google.com [209.85.216.45]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5B37E606A329 for ; Mon, 19 Oct 2026 19:25:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5B37E606A329 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=gYnQr9al Received: by mail-pj1-f45.google.com with SMTP id 98e67ed59e1d1-3ab4178ee33so1893837a91.3 for ; Mon, 19 Oct 2026 12:25:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1792437954; x=1793042754; darn=vger.kernel.org; h=mime-version:content-transfer-encoding:references:in-reply-to:to :from:subject:cc:message-id:date:content-type:from:to:cc:subject :date:message-id:reply-to:content-type; bh=Gl+QuejblNFV3uEkIxOgOsS4jX0GlJs/ROUNx5zrPn4=; b=gYnQr9alcw+J9ojP/SdeDo47GsqS10jIYNdvilfzW9uVyvOFI724RKT1A9EsWtQ3bQ OgXWmiBiwDCiu/gWReT46D/Rk9VHkHgUrKHIxf0YStCBAljm0BIHRVvWPUYzKX908eUt iCuSA6FUQ3dcvqmycwRt4gjLfOklT6OAGxuKl5xqbY72BqpfGdxLXGUQIuf+OJ5g7fu5 g/W82eNWWUviKy78jCy3BJRjKeND6NWnWoTU9lAqh7g7bOgPK8d9buk+6bjXfb3EBJwv ck0cedd6WPJoOke0xDGXsTBf/906L8PkyCNeMlUttfM6CF3DCo/JPd8cengfq/sPfTmR TcnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792437954; x=1793042754; h=mime-version:content-transfer-encoding:references:in-reply-to:to :from:subject:cc:message-id:date:content-type:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Gl+QuejblNFV3uEkIxOgOsS4jX0GlJs/ROUNx5zrPn4=; b=Zp7cp4KNlVlk+VRTsDTYpBWPsHX98YzRzRxmJ7DzV6CdIiIDPdzlo7B3ceDul9+hZO 4RhZdDx2lfBSfisn2lwXIF5AmRUH1/Onu3Ic4q1SCmNA6Ze0idS8gM2PQ/MrPGq5vTnU VWImEm4mzLXTf8ssj/x0mvwo4yQBVLZDGmbE3rBFBCECn2PHyRazAIZu/QwEvy+C/mmD 8kBjDc6Do3wRA1DVrsPpuVIE9vJurWLyW6qjoaV2X0fLe3q1prg3XinTnx9BUb5vjta8 i9GuI+L/cBrWGnikiWPn5fc59/EjNjhhf17EySNvW9mkFJVyqYKeZUCfEXBKf6JnZUWo I05w== X-Forwarded-Encrypted: i=1; AKwUvBwktbexaSQANPaAwbwhTglsxozsXg3hdyWD7q4M4ducRemseeo4JjbaClcq6BI57zOdQ+SokZk=@vger.kernel.org X-Gm-Message-State: AFq9FYKEXNgO/UMxlcaH5hUIQ+SFYgOjX7CaBhCA583mo6Rt7EPmeAq+ BqhaB/hZtBrb+a3P5H8Z97fvDWMYZ6nDV7b+WcIGQogJG3LLPy35uOKE X-Gm-Gg: AYBFou10gCLRN07vI6wYz1PEwLMYvuoWO/SESzQ13FOEv3Ayr9IfQNktS95DP2E8gbg QFBMJJgOCsxwMD4SBKAq7FJjFtl94JKkvPEo+bVpXBelIFbL9cUYg09rv1weBzLeAiAikbKTbQ5 LXkvhEFCIyoqCxUN1XM3BgpTvI8CBsOCKbZgwS5bpIQUJTx9q/T6J0S2yfT9mEuNOwSTeetjZec Ck4At5yDFZXG0derTd/goZXw7eiMi1o5jvPhQOMQD5RZdxErz5Xt3+HvkitlQIW9Lgdgc7FrwaM DsIJ/kcUw22tHP7ZVTtVArr/Een/XKkYgF3juXt36iufor6xdhtscLxURZBuDThHK0mP6CFPwCD Y8dXkaL8Swgc7xX8a1C7w6DFLMsY4hNA9WQrVQnmBRyLnBTE0ys0GxrMHQP6ElJs9/fQ3Pq/eUP Q8vJCx4Iy3PU5OuhtwB70gVpJv4OJ5kx4pD54ueXfe33tim+/JFXnGvI0u+kgtLYpzme31CcyIq QNgA8l7D+3KajxGw46TewGsXEddBcXSqOy+4qhaeKUyQ+znBYULOHPDruZaTYA0GnOs2q7oHqHY 5Tw= X-Received: by 2002:a17:90b:280e:b0:3ab:be66:ddbf with SMTP id 98e67ed59e1d1-3acef58d853mr6802869a91.54.1792437953584; Mon, 19 Oct 2026 12:25:53 -0700 (PDT) Received: from localhost ([153.61.198.245]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3acd05c9255sm8977238a91.2.2026.10.19.12.25.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 19 Oct 2026 12:25:52 -0700 (PDT) Content-Type: text/plain; charset=UTF-8 Date: Mon, 19 Oct 2026 19:25:50 +0000 Message-Id: Cc: "Andrew Lunn" , "David S . Miller" , "Eric Dumazet" , "Jakub Kicinski" , "Paolo Abeni" , "Simon Horman" , "Daniel Borkmann" , "Andrii Nakryiko" , "Eduard Zingerman" , "Kumar Kartikeya Dwivedi" , "Martin KaFai Lau" , "Song Liu" , "Yonghong Song" , "Jiri Olsa" , "Emil Tsalapatis" , "Ihor Solodrai" , "Jesper Dangaard Brouer" , "John Fastabend" , "Stanislav Fomichev" , "Steven Rostedt" , "Masami Hiramatsu" , "Mathieu Desnoyers" , "Shuah Khan" , "Kuniyuki Iwashima" , "Hangbin Liu" , "Martin Karsten" , "Masashi Honma" , , , , Subject: Re: [PATCH bpf-next v2 1/6] bpf: Add syscall common attrs support for link_create From: "Alexei Starovoitov" To: "Leon Hwang" , In-Reply-To: <20261019153628.15912-2-leon.hwang@linux.dev> References: <20261019153628.15912-1-leon.hwang@linux.dev> <20261019153628.15912-2-leon.hwang@linux.dev> X-Mailer: mkdraft (claude review draft; edit before sending) Content-Transfer-Encoding: 8bit X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 On Mon, Oct 19, 2026 at 08:36 AM Leon Hwang wrote: > + ret = bpf_log_attr_report_size(&attr_log, 0); > + if (ret) > + goto put_prog; can we drop bpf_log_attr_report_size() ? Nothing is logged when the attach succeeds, so there is no size to report, and libbpf zeroes attr_common, so log_true_size reads 0 anyway. Finalizing only when ret < 0 already keeps -EFAULT away from a live link. Then no need for the 2nd write, the log.c refactoring and the put_prog label. Something like this (compile tested only): diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 849bc91..61d100e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5856,8 +5856,11 @@ err_put: } #define BPF_LINK_CREATE_LAST_FIELD link_create.uprobe_multi.path_fd -static int link_create(union bpf_attr *attr, bpfptr_t uattr) +static int link_create(union bpf_attr *attr, bpfptr_t uattr, struct bpf_common_attr *attr_common, + bpfptr_t uattr_common, u32 size_common) { + struct bpf_verifier_log *log; + struct bpf_log_attr attr_log; struct bpf_prog *prog; int ret; @@ -5867,14 +5870,24 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) if (attr->link_create.attach_type == BPF_STRUCT_OPS) return bpf_struct_ops_link_create(attr); + log = bpf_log_attr_create_vlog(&attr_log, attr_common, uattr_common, size_common); + if (IS_ERR(log)) + return PTR_ERR(log); + prog = bpf_prog_get(attr->link_create.prog_fd); - if (IS_ERR(prog)) - return PTR_ERR(prog); + if (IS_ERR(prog)) { + bpf_log(log, "Invalid prog_fd.\n"); + ret = PTR_ERR(prog); + prog = NULL; + goto out; + } ret = bpf_prog_attach_check_attach_type(prog, attr->link_create.attach_type); - if (ret) + if (ret) { + bpf_log(log, "Invalid attach_type.\n"); goto out; + } switch (prog->type) { case BPF_PROG_TYPE_CGROUP_SKB: @@ -5953,12 +5966,19 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr) ret = bpf_uprobe_multi_link_attach(attr, prog); break; default: + bpf_log(log, "Invalid prog type.\n"); ret = -EINVAL; } out: - if (ret < 0) - bpf_prog_put(prog); + if (ret < 0) { + int err = bpf_log_attr_finalize(&attr_log, log); + + ret = err ? err : ret; + if (prog) + bpf_prog_put(prog); + } + kfree(log); return ret; } @@ -6530,7 +6550,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size, err = bpf_map_do_batch(&attr, uattr.user, BPF_MAP_DELETE_BATCH); break; case BPF_LINK_CREATE: - err = link_create(&attr, uattr); + err = link_create(&attr, uattr, &attr_common, uattr_common, size_common); break; case BPF_LINK_UPDATE: err = link_update(&attr); pw-bot: cr