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=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 71C82C433ED for ; Sun, 11 Apr 2021 20:37:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EF8061029 for ; Sun, 11 Apr 2021 20:37:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236540AbhDKUhc (ORCPT ); Sun, 11 Apr 2021 16:37:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233822AbhDKUhb (ORCPT ); Sun, 11 Apr 2021 16:37:31 -0400 Received: from mail-ot1-x329.google.com (mail-ot1-x329.google.com [IPv6:2607:f8b0:4864:20::329]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6ACD7C061574 for ; Sun, 11 Apr 2021 13:37:14 -0700 (PDT) Received: by mail-ot1-x329.google.com with SMTP id s11-20020a056830124bb029021bb3524ebeso10988305otp.0 for ; Sun, 11 Apr 2021 13:37:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=T0wu6sj4bStEBpLbQzv4rYhAmCgr+WzK85ZIhvG4PZc=; b=UWm1fav4Q2tgwBoDQBx0wqfMrLJcpM+uX1RIn5OWpR3PxcK0VWQhsg3+aEPgtiG79r Xh0mXva7fY1Zn5AlwT1uxWXjOUu2hP//4Pj2WU6WHHngQHNsyoF9ErcSEgyTnmCwhIRx UxhoRCD0+mkj8kaLn4vH4N65ejKL5AOZrXTLM6EeI/j/gI6pknPNZCTN7gJk1jOT/cnB /M0EyHyNModf7VGIVXRfEiBRUo78OSMyjGG1u5TlmJqYfuN7QH6wytFSC+It1lxeBIs0 xBZd5OCnMeEODdULHm3J80gPo7q2QYV8HzoI6KPaA/JoIZdNTyxgbHCAwlMH7X3OWGZt vTdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=T0wu6sj4bStEBpLbQzv4rYhAmCgr+WzK85ZIhvG4PZc=; b=da6jU/EZMSzKujkxkQUpnxwtEiAjIH3yca3XqX6WxIDxYn2us4zWnI/oRtuKWUMODK xL1Z5S/KPSAywISeYmQ2RxXjhSG71jlPEn8gd0vQ+0M0E4jatf5hKtVyX5LxlYLV5uJK P1xNrCUp75hy8qeRAO8Vwzy+0eOotlvCM0eZGCEfhlAixbHHRpv1Lp/FPV/8oDY+jYjf JmapMreX3FFXVO4j5SqJF3iUyKhohdWIUnu+iHt6PywITn7XzuIdeAG4yjcbUZY2TadO 07ZRUYF0+dydlikZOvu932pJLxL/CRUfTnqn0mDFvC2as8iHqCRlxlA1DX5RBvYUvz4e 2NxA== X-Gm-Message-State: AOAM532YJUlKRu26nmPNmQw0Rc+h4hYTgEBxTuyncbHJtSbYS4PpHNk9 ZzZomDFbutNTSIAdnm8vbmc= X-Google-Smtp-Source: ABdhPJywcCsZat3ECtk89Ngxwd54uJIXCBAbX0Y1Evq2U72h1zC+WngNnxkHHgHGvI4A8HQblOGTOA== X-Received: by 2002:a05:6830:3497:: with SMTP id c23mr20381727otu.344.1618173433784; Sun, 11 Apr 2021 13:37:13 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id t2sm1799858ool.18.2021.04.11.13.37.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 11 Apr 2021 13:37:13 -0700 (PDT) Sender: Guenter Roeck Subject: Re: [PATCH net] virtio_net: Do not pull payload in skb->head To: Eric Dumazet Cc: Eric Dumazet , "David S . Miller" , Jakub Kicinski , netdev , Xuan Zhuo , "Michael S. Tsirkin" , Jason Wang , virtualization@lists.linux-foundation.org References: <20210402132602.3659282-1-eric.dumazet@gmail.com> <20210411134329.GA132317@roeck-us.net> From: Guenter Roeck Autocrypt: addr=linux@roeck-us.net; keydata= xsFNBE6H1WcBEACu6jIcw5kZ5dGeJ7E7B2uweQR/4FGxH10/H1O1+ApmcQ9i87XdZQiB9cpN RYHA7RCEK2dh6dDccykQk3bC90xXMPg+O3R+C/SkwcnUak1UZaeK/SwQbq/t0tkMzYDRxfJ7 nyFiKxUehbNF3r9qlJgPqONwX5vJy4/GvDHdddSCxV41P/ejsZ8PykxyJs98UWhF54tGRWFl 7i1xvaDB9lN5WTLRKSO7wICuLiSz5WZHXMkyF4d+/O5ll7yz/o/JxK5vO/sduYDIlFTvBZDh gzaEtNf5tQjsjG4io8E0Yq0ViobLkS2RTNZT8ICq/Jmvl0SpbHRvYwa2DhNsK0YjHFQBB0FX IdhdUEzNefcNcYvqigJpdICoP2e4yJSyflHFO4dr0OrdnGLe1Zi/8Xo/2+M1dSSEt196rXaC kwu2KgIgmkRBb3cp2vIBBIIowU8W3qC1+w+RdMUrZxKGWJ3juwcgveJlzMpMZNyM1jobSXZ0 VHGMNJ3MwXlrEFPXaYJgibcg6brM6wGfX/LBvc/haWw4yO24lT5eitm4UBdIy9pKkKmHHh7s jfZJkB5fWKVdoCv/omy6UyH6ykLOPFugl+hVL2Prf8xrXuZe1CMS7ID9Lc8FaL1ROIN/W8Vk BIsJMaWOhks//7d92Uf3EArDlDShwR2+D+AMon8NULuLBHiEUQARAQABzTJHdWVudGVyIFJv ZWNrIChMaW51eCBhY2NvdW50KSA8bGludXhAcm9lY2stdXMubmV0PsLBgQQTAQIAKwIbAwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4ACGQEFAlVcphcFCRmg06EACgkQyx8mb86fmYFg0RAA nzXJzuPkLJaOmSIzPAqqnutACchT/meCOgMEpS5oLf6xn5ySZkl23OxuhpMZTVX+49c9pvBx hpvl5bCWFu5qC1jC2eWRYU+aZZE4sxMaAGeWenQJsiG9lP8wkfCJP3ockNu0ZXXAXwIbY1O1 c+l11zQkZw89zNgWgKobKzrDMBFOYtAh0pAInZ9TSn7oA4Ctejouo5wUugmk8MrDtUVXmEA9 7f9fgKYSwl/H7dfKKsS1bDOpyJlqhEAH94BHJdK/b1tzwJCFAXFhMlmlbYEk8kWjcxQgDWMu GAthQzSuAyhqyZwFcOlMCNbAcTSQawSo3B9yM9mHJne5RrAbVz4TWLnEaX8gA5xK3uCNCeyI sqYuzA4OzcMwnnTASvzsGZoYHTFP3DQwf2nzxD6yBGCfwNGIYfS0i8YN8XcBgEcDFMWpOQhT Pu3HeztMnF3HXrc0t7e5rDW9zCh3k2PA6D2NV4fews9KDFhLlTfCVzf0PS1dRVVWM+4jVl6l HRIAgWp+2/f8dx5vPc4Ycp4IsZN0l1h9uT7qm1KTwz+sSl1zOqKD/BpfGNZfLRRxrXthvvY8 BltcuZ4+PGFTcRkMytUbMDFMF9Cjd2W9dXD35PEtvj8wnEyzIos8bbgtLrGTv/SYhmPpahJA l8hPhYvmAvpOmusUUyB30StsHIU2LLccUPPOwU0ETofVZwEQALlLbQeBDTDbwQYrj0gbx3bq 7kpKABxN2MqeuqGr02DpS9883d/t7ontxasXoEz2GTioevvRmllJlPQERVxM8gQoNg22twF7 pB/zsrIjxkE9heE4wYfN1AyzT+AxgYN6f8hVQ7Nrc9XgZZe+8IkuW/Nf64KzNJXnSH4u6nJM J2+Dt274YoFcXR1nG76Q259mKwzbCukKbd6piL+VsT/qBrLhZe9Ivbjq5WMdkQKnP7gYKCAi pNVJC4enWfivZsYupMd9qn7Uv/oCZDYoBTdMSBUblaLMwlcjnPpOYK5rfHvC4opxl+P/Vzyz 6WC2TLkPtKvYvXmdsI6rnEI4Uucg0Au/Ulg7aqqKhzGPIbVaL+U0Wk82nz6hz+WP2ggTrY1w ZlPlRt8WM9w6WfLf2j+PuGklj37m+KvaOEfLsF1v464dSpy1tQVHhhp8LFTxh/6RWkRIR2uF I4v3Xu/k5D0LhaZHpQ4C+xKsQxpTGuYh2tnRaRL14YMW1dlI3HfeB2gj7Yc8XdHh9vkpPyuT nY/ZsFbnvBtiw7GchKKri2gDhRb2QNNDyBnQn5mRFw7CyuFclAksOdV/sdpQnYlYcRQWOUGY HhQ5eqTRZjm9z+qQe/T0HQpmiPTqQcIaG/edgKVTUjITfA7AJMKLQHgp04Vylb+G6jocnQQX JqvvP09whbqrABEBAAHCwWUEGAECAA8CGwwFAlVcpi8FCRmg08MACgkQyx8mb86fmYHNRQ/+ J0OZsBYP4leJvQF8lx9zif+v4ZY/6C9tTcUv/KNAE5leyrD4IKbnV4PnbrVhjq861it/zRQW cFpWQszZyWRwNPWUUz7ejmm9lAwPbr8xWT4qMSA43VKQ7ZCeTQJ4TC8kjqtcbw41SjkjrcTG wF52zFO4bOWyovVAPncvV9eGA/vtnd3xEZXQiSt91kBSqK28yjxAqK/c3G6i7IX2rg6pzgqh hiH3/1qM2M/LSuqAv0Rwrt/k+pZXE+B4Ud42hwmMr0TfhNxG+X7YKvjKC+SjPjqp0CaztQ0H nsDLSLElVROxCd9m8CAUuHplgmR3seYCOrT4jriMFBtKNPtj2EE4DNV4s7k0Zy+6iRQ8G8ng QjsSqYJx8iAR8JRB7Gm2rQOMv8lSRdjva++GT0VLXtHULdlzg8VjDnFZ3lfz5PWEOeIMk7Rj trjv82EZtrhLuLjHRCaG50OOm0hwPSk1J64R8O3HjSLdertmw7eyAYOo4RuWJguYMg5DRnBk WkRwrSuCn7UG+qVWZeKEsFKFOkynOs3pVbcbq1pxbhk3TRWCGRU5JolI4ohy/7JV1TVbjiDI HP/aVnm6NC8of26P40Pg8EdAhajZnHHjA7FrJXsy3cyIGqvg9os4rNkUWmrCfLLsZDHD8FnU mDW4+i+XlNFUPUYMrIKi9joBhu18ssf5i5Q= Message-ID: <0f63dc52-ea72-16b6-7dcd-efb24de0c852@roeck-us.net> Date: Sun, 11 Apr 2021 13:37:10 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 4/11/21 8:06 AM, Eric Dumazet wrote: > On Sun, Apr 11, 2021 at 3:43 PM Guenter Roeck wrote: > >> This patch causes a virtio-net interface failure when booting sh4 images >> in qemu. The test case is nothing special: Just try to get an IP address >> using udhcpc. If it fails, udhcpc reports: >> >> udhcpc: started, v1.33.0 >> udhcpc: sending discover >> FAIL >> > > Can you investigate where the incoming packet is dropped ? > Unless I am missing something, packets are not dropped. It looks more like udhcpc gets bad indigestion in the receive path and exits immediately. Plus, it doesn't happen all the time; sometimes it receives the discover response and is able to obtain an IP address. Overall this is quite puzzling since udhcpc exits immediately when the problem is seen, no matter which option I give it on the command line; it should not really do that. Guenter