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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 9CD9AC48BD4 for ; Tue, 25 Jun 2019 17:03:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7237A20883 for ; Tue, 25 Jun 2019 17:03:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="luKHFtP1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729794AbfFYRDt (ORCPT ); Tue, 25 Jun 2019 13:03:49 -0400 Received: from mail-wr1-f43.google.com ([209.85.221.43]:33486 "EHLO mail-wr1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728130AbfFYRDt (ORCPT ); Tue, 25 Jun 2019 13:03:49 -0400 Received: by mail-wr1-f43.google.com with SMTP id n9so18784880wru.0 for ; Tue, 25 Jun 2019 10:03:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=GEQ2iPLIX3P9r+aam6xPIL5jitO/ctg9DQvewvUwftI=; b=luKHFtP1jap/OOvbZWvE4/pF16+oNiU2GFQSQc3f5RhSM4pFSQMPnqFGlseuHxAB9P jvseW6gizODix4PSAYU17I7wbwhyCPsdeaCUsfMiYpEq3Hox8jh2nhySmD4OiKzHCaaX dqtpDvqr9q9bbrK0MT4IALPgSjiPCrRCIaDPADML75cjKHo1l8Wf31t3frd2yjaJOqtw UFd4T0BjcFC6UGvgRBeaCiPu2ajnHjzeRYDmDFtdAXiFrt4TJLMpC342lwrb7gab1hRg IOTDJ1iAC6VCJGiGDr6oj/xHMMUYFnyiEwq2mu8wtaKIMaORGxYCMPLhvf0VM6wgNHi9 Fklw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=GEQ2iPLIX3P9r+aam6xPIL5jitO/ctg9DQvewvUwftI=; b=DqCUJtxKtfErk6gvVOops6HdbCsbONfxBJESnHGTcXQrgl9dozUAjhUVQn96mwSMI6 BOvnJPBlcA+cZwJNosAowZ0RWGeqjzdVNHFSjViNDQKJL/YzGkgMiyzF0O5OZK0Df8Eb +usyHXCLuZz6LnrIFA5VvOIVCYOck7jMGUkjGrknWJjaf7R8mYGPI0YfzHS54/K0+4T9 GfGyD7BBLsBhz4tYqZjF8J2iOtp/iTDwcNnAGTHfIfxTOGT1N/0YV3rb9NMY5AzSxHdn Im/s4KF9x9PSTUQOtvkI893VqNP8EpZyrh8NtMNn1ed+WKC0v2ESXJ/H5+tumIqEIYZ0 Rx1A== X-Gm-Message-State: APjAAAUh2eD7i0U8fFFzHy/KWtiNLE5NJ3mzngZ2kEs5nB6ae1Qx+A3q ar6L0k7qpQbjqEbQUk5pGm8= X-Google-Smtp-Source: APXvYqybHqbQSG/93WN+oJVVCshrG9z6SSYZtyUq7jOPWzfWoGzXOOhDs5S2jSbOAUKhdFUcG5xnUA== X-Received: by 2002:adf:9bd3:: with SMTP id e19mr37310117wrc.38.1561482226961; Tue, 25 Jun 2019 10:03:46 -0700 (PDT) Received: from [192.168.8.147] (104.84.136.77.rev.sfr.net. [77.136.84.104]) by smtp.gmail.com with ESMTPSA id t12sm15996718wrw.53.2019.06.25.10.03.42 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Tue, 25 Jun 2019 10:03:46 -0700 (PDT) Subject: Re: Removing skb_orphan() from ip_rcv_core() To: Daniel Borkmann , Joe Stringer , Florian Westphal Cc: netdev , john fastabend , Lorenz Bauer , Jakub Sitnicki , Paolo Abeni , Flavio Leitner , ast@kernel.org References: <20190621205935.og7ajx57j7usgycq@breakpoint.cc> <4deff7d7-cc10-090d-86f2-850148fdf032@iogearbox.net> From: Eric Dumazet Message-ID: <5f916eb2-9971-f3a8-fac8-b4b51cd881b0@gmail.com> Date: Tue, 25 Jun 2019 19:03:36 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <4deff7d7-cc10-090d-86f2-850148fdf032@iogearbox.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 6/25/19 2:35 AM, Daniel Borkmann wrote: > > But wasn't the whole point of 9c4c325252c5 ("skbuff: preserve sock reference when > scrubbing the skb.") to defer orphaning to as late as possible? If I'm not missing > anything, then above would reintroduce the issues that 9c4c325252c5 was trying to > solve wrt TSQ/XPS/etc when skb was sent via veth based data path to cross netns and > then forwarded to phys dev for transmission; meaning, skb->sk is lost at the point > of dev_queue_xmit() for the latter. A side-effect this would also have is that this > changes behavior again for tc egress programs sitting on phys dev (e.g. querying > sock cookie or other related features). Unless we can detect/decide that a packet going through veth pair is going to be locally consumed, or forwarded to a physical device (another ndo_start_xmit()), we need to skb_orphan() the packet, exactly the same way than loopback ndo_start_xmit() (We could have setups where these packets going through lo interface could be forwarded to a NIC...) Backpressure is a best effort, we should not make it an absolute requirement and prevent doing early demux as early as possible in RX path.