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 AFB71C001DF for ; Wed, 2 Aug 2023 06:52:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232777AbjHBGwg (ORCPT ); Wed, 2 Aug 2023 02:52:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232813AbjHBGwU (ORCPT ); Wed, 2 Aug 2023 02:52:20 -0400 Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCE962D53; Tue, 1 Aug 2023 23:51:45 -0700 (PDT) Received: by mail-pl1-x62b.google.com with SMTP id d9443c01a7336-1bbd2761f1bso54462795ad.2; Tue, 01 Aug 2023 23:51:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690959102; x=1691563902; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=7ZOYz5tJWIm5wwiu4clNWQAkqTwhMrt2CWLKqUdg8b0=; b=IzeHwt2JyZr1omnyxl/9LlDPoarPSoZBsZtf6OM5pnMbxIsuze+GLyevO8tgqGqZ/2 dK4ubBy95WuUpzappL98/g6mN2HXuvZw9m7kv6ySU2eYa3pQ3y7o3uRuxoEzVyApW56Y HOeO9G+M8qSJkVOHsRIa2Ofvrl6n2Fz6Obb7I5fiJamdEE0ffosKXAwT+YZBDhGGMEcb H6abgTo8k1KZJ5K9oKQntO/ARoDtc+Rerdvb+xQAIUsF76Atq3xe9JeoH1pfUWYpqeIz g4N7+mgwH3CfTTBmcIfgO8/toINwvbh1V+3QtFzTzz5rigL8Ia3lGCGe8vDYzIIHl6I6 xhZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690959102; x=1691563902; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=7ZOYz5tJWIm5wwiu4clNWQAkqTwhMrt2CWLKqUdg8b0=; b=ANURGCDyaETQAX4QJrBcWZQ3iQhl9MFMmNce/W4xagrfuqlEC83mXJm1d6X/7f1MLm oU1rXSLq7Ib5koA3qyw0SVu/oolL7sZ5IysTShsWqXZIcxdna6K0PattyDS2Hn7bIr3y HvxiOQMV6uZ039B6BZ8mLbH2X+rIfbsVllGTNgOvAlEh7PQXb1k+PZzEzUqtaKwE0doU k4Bgo/zrKOGz0p9s5px9zkNYgEctNN5MVHyfX7tTPNxCmVj6qx/UitKLJkI6M4SQKVys UwF2OmVni+10yGf/LGPvqygBhcGpgQfrnZwwSdwA3B1twZ3bH8hCG7b3z/GyRtFGch7A s3XA== X-Gm-Message-State: ABy/qLYQZ5CTRhzuN73oqmVwy+sAV1PL8iraYZ72FSlpUVr+LjY1Ir9M H5zQwYXivfFfqhR8j2/I6hA/JdaCI94D2I9W X-Google-Smtp-Source: APBJJlHPUMf6CpGNUzLl+072yFaIiU/Vjiu2Lyni6TT2M0vLzGFtjD/rY1bYh8RKhME4IwbsD7lD6g== X-Received: by 2002:a17:902:c20c:b0:1b8:adc:7c3d with SMTP id 12-20020a170902c20c00b001b80adc7c3dmr15322879pll.40.1690959102532; Tue, 01 Aug 2023 23:51:42 -0700 (PDT) Received: from [10.22.68.111] ([122.11.166.8]) by smtp.gmail.com with ESMTPSA id g8-20020a1709029f8800b001a80ad9c599sm11496477plq.294.2023.08.01.23.51.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 01 Aug 2023 23:51:42 -0700 (PDT) Message-ID: <1483f6db-35a8-849b-9bda-00ad5aa81eff@gmail.com> Date: Wed, 2 Aug 2023 14:51:35 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH bpf-next v5 1/2] bpf, xdp: Add tracepoint to xdp attaching failure Content-Language: en-US To: Jakub Kicinski Cc: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, hawk@kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, mykolal@fb.com, shuah@kernel.org, tangyeechou@gmail.com, kernel-patches-bot@fb.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20230801142621.7925-1-hffilwlqm@gmail.com> <20230801142621.7925-2-hffilwlqm@gmail.com> <20230801150826.6f617919@kernel.org> From: Leon Hwang In-Reply-To: <20230801150826.6f617919@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On 2/8/23 06:08, Jakub Kicinski wrote: > On Tue, 1 Aug 2023 22:26:20 +0800 Leon Hwang wrote: >> When error happens in dev_xdp_attach(), it should have a way to tell >> users the error message like the netlink approach. >> >> To avoid breaking uapi, adding a tracepoint in bpf_xdp_link_attach() is >> an appropriate way to notify users the error message. >> >> Hence, bpf libraries are able to retrieve the error message by this >> tracepoint, and then report the error message to users. > > Whatevered-by: Jakub Kicinski ? Oh, it's not responsible for libraries to retrieve the error message. It should be users' responsibility. Sorry for the misguiding text. In the previous patch[0], which changes uapi, it's able to back-propagate the error message from dev_xdp_attach() to userspace through BPF syscall. Then, tracepoint idea is suggested to avoid changing uapi. I do agree to implement a tracepoint to avoid changing uapi. [0] bpf: Introduce user log https://lore.kernel.org/bpf/20230708040750.72570-1-hffilwlqm@gmail.com/ Thanks, Leon