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, URIBL_BLOCKED,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 D5355C352A3 for ; Tue, 11 Feb 2020 07:42:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B3F20206D7 for ; Tue, 11 Feb 2020 07:42:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727723AbgBKHmp (ORCPT ); Tue, 11 Feb 2020 02:42:45 -0500 Received: from ivanoab7.miniserver.com ([37.128.132.42]:42908 "EHLO www.kot-begemot.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726219AbgBKHmp (ORCPT ); Tue, 11 Feb 2020 02:42:45 -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 1j1QBs-0007Vn-1k; Tue, 11 Feb 2020 07:42:40 +0000 Received: from sleer.kot-begemot.co.uk ([192.168.3.72]) by jain.kot-begemot.co.uk with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1j1QBp-0007Nw-Mr; Tue, 11 Feb 2020 07:42:39 +0000 Subject: Re: [PATCH] virtio: Work around frames incorrectly marked as gso To: Jason Wang , netdev@vger.kernel.org Cc: linux-um@lists.infradead.org, mst@redhat.com, virtualization@lists.linux-foundation.org References: <20191209104824.17059-1-anton.ivanov@cambridgegreys.com> <57230228-7030-c65f-a24f-910ca52bbe9e@cambridgegreys.com> From: Anton Ivanov Organization: Cambridge Greys Message-ID: <918222d9-816a-be70-f8af-b8dfcb586240@cambridgegreys.com> Date: Tue, 11 Feb 2020 07:42:37 +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: 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 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. -- Anton R. Ivanov Cambridgegreys Limited. Registered in England. Company Number 10273661 https://www.cambridgegreys.com/