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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 4AC12C2BA83 for ; Wed, 12 Feb 2020 10:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 25EE920675 for ; Wed, 12 Feb 2020 10:03:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728848AbgBLKDk (ORCPT ); Wed, 12 Feb 2020 05:03:40 -0500 Received: from ivanoab7.miniserver.com ([37.128.132.42]:44996 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728715AbgBLKDk (ORCPT ); Wed, 12 Feb 2020 05:03:40 -0500 Received: from tun252.jain.kot-begemot.co.uk ([192.168.18.6] helo=jain.kot-begemot.co.uk) by www.kot-begemot.co.uk with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1j1orl-0003s6-Kq; Wed, 12 Feb 2020 10:03:33 +0000 Received: from jain.kot-begemot.co.uk ([192.168.3.3]) by jain.kot-begemot.co.uk with esmtp (Exim 4.92) (envelope-from ) id 1j1orj-0008KU-Ct; Wed, 12 Feb 2020 10:03:33 +0000 Subject: Re: [PATCH] virtio: Work around frames incorrectly marked as gso To: "Michael S. Tsirkin" Cc: netdev@vger.kernel.org, Jason Wang , linux-um@lists.infradead.org, virtualization@lists.linux-foundation.org References: <20191209104824.17059-1-anton.ivanov@cambridgegreys.com> <57230228-7030-c65f-a24f-910ca52bbe9e@cambridgegreys.com> <918222d9-816a-be70-f8af-b8dfcb586240@cambridgegreys.com> <20200211053502-mutt-send-email-mst@kernel.org> From: Anton Ivanov Message-ID: <8e730fe1-3129-de8d-bcb6-d5e10695238a@cambridgegreys.com> Date: Wed, 12 Feb 2020 10:03:31 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200211053502-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Clacks-Overhead: GNU Terry Pratchett Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 11/02/2020 10:37, Michael S. Tsirkin wrote: > On Tue, Feb 11, 2020 at 07:42:37AM +0000, Anton Ivanov wrote: >> On 11/02/2020 02:51, Jason Wang wrote: >>> >>> On 2020/2/11 上午12:55, Anton Ivanov wrote: >>>> >>>> >>>> On 09/12/2019 10:48, anton.ivanov@cambridgegreys.com wrote: >>>>> From: Anton Ivanov >>>>> >>>>> Some of the frames marked as GSO which arrive at >>>>> virtio_net_hdr_from_skb() have no GSO_TYPE, no >>>>> fragments (data_len = 0) and length significantly shorter >>>>> than the MTU (752 in my experiments). >>>>> >>>>> This is observed on raw sockets reading off vEth interfaces >>>>> in all 4.x and 5.x kernels I tested. >>>>> >>>>> These frames are reported as invalid while they are in fact >>>>> gso-less frames. >>>>> >>>>> This patch marks the vnet header as no-GSO for them instead >>>>> of reporting it as invalid. >>>>> >>>>> Signed-off-by: Anton Ivanov >>>>> --- >>>>>   include/linux/virtio_net.h | 8 ++++++-- >>>>>   1 file changed, 6 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h >>>>> index 0d1fe9297ac6..d90d5cff1b9a 100644 >>>>> --- a/include/linux/virtio_net.h >>>>> +++ b/include/linux/virtio_net.h >>>>> @@ -112,8 +112,12 @@ static inline int >>>>> virtio_net_hdr_from_skb(const struct sk_buff *skb, >>>>>               hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; >>>>>           else if (sinfo->gso_type & SKB_GSO_TCPV6) >>>>>               hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; >>>>> -        else >>>>> -            return -EINVAL; >>>>> +        else { >>>>> +            if (skb->data_len == 0) >>>>> +                hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; >>>>> +            else >>>>> +                return -EINVAL; >>>>> +        } >>>>>           if (sinfo->gso_type & SKB_GSO_TCP_ECN) >>>>>               hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; >>>>>       } else >>>>> >>>> >>>> ping. >>>> >>> >>> Do you mean gso_size is set but gso_type is not? Looks like a bug >>> elsewhere. >>> >>> Thanks >>> >>> >> Yes. >> >> I could not trace it where it is coming from. >> >> I see it when doing recvmmsg on raw sockets in the UML vector network >> drivers. >> > > I think we need to find the culprit and fix it there, lots of other things > can break otherwise. > Just printing out skb->dev->name should do the trick, no? I will rebuild my rig and retest (it's been a while since I worked on this bug). In theory, it should be veth - the test is over a vEth pair and all frames are locally originated by iperf. In practice - I will retest and post the results sometimes later today. Brgds, > > > >> -- >> Anton R. Ivanov >> Cambridgegreys Limited. Registered in England. Company Number 10273661 >> https://www.cambridgegreys.com/ > > > _______________________________________________ > linux-um mailing list > linux-um@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-um > -- Anton R. Ivanov Cambridgegreys Limited. Registered in England. Company Number 10273661 https://www.cambridgegreys.com/