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=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS 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 5DE5BC10F27 for ; Mon, 9 Mar 2020 15:43:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32AEE21D56 for ; Mon, 9 Mar 2020 15:43:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="TBWHDZVh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727060AbgCIPnT (ORCPT ); Mon, 9 Mar 2020 11:43:19 -0400 Received: from mail-yw1-f65.google.com ([209.85.161.65]:45061 "EHLO mail-yw1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726804AbgCIPnT (ORCPT ); Mon, 9 Mar 2020 11:43:19 -0400 Received: by mail-yw1-f65.google.com with SMTP id d206so10504666ywa.12 for ; Mon, 09 Mar 2020 08:43:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=485SssXkW+H0mLX40BLOHwY75nYIzJ98vMhLiSaXO4E=; b=TBWHDZVh/IUXDpbMbnC7qBGK2AoV46NiJVIUG8NalFrPzyBaDXYRWFiu/DRt5hG+Re 32F0L+WA0ZHWaBgH52CTC6j6sJ19EoYnz+6YhDdvEuACK8N+wFxsz9qAwEsD3UCayTiC mOfIIkNmBGLq2Dzj2bsR0a6Aap6wYvn6hD6yLgdkJiiyVHWIJC4aohuPjxKFFRiuwWxU MliMMKqLH3CkirCWO+PyjLZW+xm70PJZUNVgYjUiaAgt0cN/JYXaYDPfjo1yjfsMFA1+ Jcb3GHMK/9kIK1XribTStEi5aBSlgd76yUR78RgWXplIf1YbgAuHDseD+FdGCQrgXZMv 7ijQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=485SssXkW+H0mLX40BLOHwY75nYIzJ98vMhLiSaXO4E=; b=VG0/McU7WWFXvY3CR8TCEkTySocr8h9Vj37A2/Wgxpsf/LDQ58yrT2IWKXBspwLAz3 pOXj6/iP6B4xnnkFinbtZuiA0k/AG2fY21Bhv4YX2RHNyHI8CxK8w0TZp9wFD9OvuAo1 1/Saryabjf8qXavRPe90ehU/UwRo6y7cPa9X4P6EJe7mSGoU8QuYqfKSxig5EfbBOklV GyDR1NuDE9KWn8vCtpjLScEYVB7S7uKyx/dIXydSn8E/CwEw2LB1ERXsEf3CInEm5/qi gfWMXlLbmQjbMU9+9fbNkdayPteFuXulVkiSJz1z8wYNnTrNvKeNAspAUS4EYF7BpSP7 ygxA== X-Gm-Message-State: ANhLgQ2ZcKvWqylPsrdA/3vBCzIL+PtehjxCxsAI6d/Z2fPYZCKV3TIZ vQTBe/octfG26HRP7OQGZLbOfLjR X-Google-Smtp-Source: ADFU+vv1C9CgLORRnNaaAodoxDdax/M8c0Q1dR+pTORDrfF5v24K66W6zDi9KG9tLGuGN8YmitvGBg== X-Received: by 2002:a5b:c8d:: with SMTP id i13mr17281654ybq.480.1583768597827; Mon, 09 Mar 2020 08:43:17 -0700 (PDT) Received: from mail-yw1-f53.google.com (mail-yw1-f53.google.com. [209.85.161.53]) by smtp.gmail.com with ESMTPSA id o127sm18107413ywf.43.2020.03.09.08.43.17 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Mar 2020 08:43:17 -0700 (PDT) Received: by mail-yw1-f53.google.com with SMTP id d206so10504576ywa.12 for ; Mon, 09 Mar 2020 08:43:17 -0700 (PDT) X-Received: by 2002:a25:cc8a:: with SMTP id l132mr18224208ybf.178.1583768596496; Mon, 09 Mar 2020 08:43:16 -0700 (PDT) MIME-Version: 1.0 References: <20200309153435.32109-1-willemdebruijn.kernel@gmail.com> In-Reply-To: <20200309153435.32109-1-willemdebruijn.kernel@gmail.com> From: Willem de Bruijn Date: Mon, 9 Mar 2020 11:42:40 -0400 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH net] net/packet: tpacket_rcv: do not increment ring index on drop To: Willem de Bruijn Cc: Network Development , David Miller , "Michael S. Tsirkin" Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Mar 9, 2020 at 11:34 AM Willem de Bruijn wrote: > > From: Willem de Bruijn > > In one error case, tpacket_rcv drops packets after incrementing the > ring producer index. > > If this happens, it does not update tp_status to TP_STATUS_USER and > thus the reader is stalled for an iteration of the ring, causing out > of order arrival. > > The only such error path is when virtio_net_hdr_from_skb fails due > to encountering an unknown GSO type. > > Signed-off-by: Willem de Bruijn Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.") I forgot to add the Fixes tag, sorry. This goes back to the introduction of GSO support for virtio_net. The discussion then explicitly arrived at deciding to fail on an unknown type (SKB_GSO_FCOE). Which is why I asked the question here whether we want to revisit that choice or leave as is.