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=DKIM_SIGNED,DKIM_VALID, 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 5D80DC4360C for ; Sat, 12 Oct 2019 19:40:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D39720700 for ; Sat, 12 Oct 2019 19:40:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cogentembedded-com.20150623.gappssmtp.com header.i=@cogentembedded-com.20150623.gappssmtp.com header.b="F4fTfDBg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729516AbfJLTe4 (ORCPT ); Sat, 12 Oct 2019 15:34:56 -0400 Received: from mail-lj1-f194.google.com ([209.85.208.194]:35137 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729280AbfJLTe4 (ORCPT ); Sat, 12 Oct 2019 15:34:56 -0400 Received: by mail-lj1-f194.google.com with SMTP id m7so12934708lji.2 for ; Sat, 12 Oct 2019 12:34:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cogentembedded-com.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:organization:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=wgrBphK2ZKLKLKQJBxJ+04hzcg40mP5P57Sgt0XI3AI=; b=F4fTfDBgS2eid7oSFip/FDEDfPXrx4FrxGQxqvEl6QMaNqZR+i+EZqafXAthP5P9+x yHDghCUdv3wc8EPxs/921ZARMAob8jyZMCrTSv0zK99uzKHDGI8lw/wBsKCd17vOs5fB rUJsYkHvgyQ4O+KQlKvYeWoUVRTtnYMV1MlGJD97zCMfaEMG9XKwULB/glNYZpP06Wnv JjMCb4X+FZWgQRRmLr3t4MvFWuS0hGzksJJ8e9Ubv7NGr8M4YDefwzP6AcY0TZ2fj5Io 0GjbMofkS1RYHQNwGyRtHqTtYj9UuTHx+IUHTuF1vjhdUF74ZGYN6abZhYWqg/cwvttF nt1g== 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:organization :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=wgrBphK2ZKLKLKQJBxJ+04hzcg40mP5P57Sgt0XI3AI=; b=iXjL3xAuhiTz6X6QZZGa9D0x5kcn4Q30BWLyMcBD/Xr5hLyFNtrbA+Auei3EI0MYZs R7sItYRL2aFEoxPYZz2GWRnI0oWWcSRUZMxXQNr/xXmvLZpETjsDShuztL/Jzd/EvNbz uRViQKLQN3qSJu3AyFjKlTlTFmUTXtgAXTqBW7fOpFxexzULG15+mPiOr+kwGFFdVv6/ EFRZobbzs0joMqVUr8jtoZmN4WGKQ2BpDXP3u6FmB5Z2hhpJ4anbnuQOzgjykvrP1fJM 2HDsyLB/1flSqLfPUsrdIylJyW6Lc0VMuz957DGjn0v3eBBBEZbpnFjYseLo6s2H6wYB USnw== X-Gm-Message-State: APjAAAU4JYXkJlxkZwenIZ529zQMNHrDLKUm/CIIYIkOyTEGGp1OQ5ME zhQmyiZNIysFQ0eLfb9XdaGycQ== X-Google-Smtp-Source: APXvYqwpJi0zA6Rs0Ts729eEXfP/zzoIHE+HxlK5BMebEI/QXwfiMx4thmdG6MDW+kQBR7LX7eF+hw== X-Received: by 2002:a05:651c:1213:: with SMTP id i19mr6593579lja.19.1570908892385; Sat, 12 Oct 2019 12:34:52 -0700 (PDT) Received: from wasted.cogentembedded.com ([2a00:1fa0:42ce:cb54:d810:b267:5380:ba01]) by smtp.gmail.com with ESMTPSA id g21sm2991604lje.67.2019.10.12.12.34.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 12 Oct 2019 12:34:51 -0700 (PDT) Subject: Re: [PATCH net] net: sched: act_mirred: drop skb's dst_entry in ingress redirection To: Zhiyuan Hou , Jamal Hadi Salim , Cong Wang , Jiri Pirko , "David S . Miller" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20191012071620.8595-1-zhiyuan2048@linux.alibaba.com> From: Sergei Shtylyov Organization: Cogent Embedded Message-ID: <2ad15b96-156d-7b71-0e37-74ceeacade35@cogentembedded.com> Date: Sat, 12 Oct 2019 22:34:50 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20191012071620.8595-1-zhiyuan2048@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-MW Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hello! On 10/12/2019 10:16 AM, Zhiyuan Hou wrote: > In act_mirred's ingress redirection, if the skb's dst_entry is valid > when call function netif_receive_skb, the fllowing l3 stack process Following or flowing? > (ip_rcv_finish_core) will check dst_entry and skip the routing > decision. Using the old dst_entry is unexpected and may discard the > skb in some case. For example dst->dst_input points to dst_discard. > > This patch drops the skb's dst_entry before calling netif_receive_skb > so that the skb can be made routing decision like a normal ingress > skb. > > Signed-off-by: Zhiyuan Hou > --- > net/sched/act_mirred.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c > index 9ce073a05414..6108a64c0cd5 100644 > --- a/net/sched/act_mirred.c > +++ b/net/sched/act_mirred.c [...] > @@ -298,8 +299,10 @@ static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, > > if (!want_ingress) > err = dev_queue_xmit(skb2); > - else > + else { > + skb_dst_drop(skb2); > err = netif_receive_skb(skb2); > + } If you introduce {} in one *if* branch, {} should be added to the other branches as well, says CodingStyle. [...] MBR, Sergei