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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8923C6FD1F for ; Mon, 13 Mar 2023 16:32:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230139AbjCMQcU (ORCPT ); Mon, 13 Mar 2023 12:32:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229689AbjCMQcR (ORCPT ); Mon, 13 Mar 2023 12:32:17 -0400 Received: from mail-ed1-x52d.google.com (mail-ed1-x52d.google.com [IPv6:2a00:1450:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 178E57B48D for ; Mon, 13 Mar 2023 09:31:48 -0700 (PDT) Received: by mail-ed1-x52d.google.com with SMTP id ek18so19958396edb.6 for ; Mon, 13 Mar 2023 09:31:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tessares.net; s=google; t=1678725080; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=iC/9rxrLtt9j5YQSFIj4r+xqIhr4OIPVnE5VID9BZVo=; b=YtADCUojuhirIfFRQL1K75A264lIItj+966LATxLRu6s7fqnP9LTwc+RnSBOr2EcbT E9kGP2na4r89BHbgbTu7AZ1e5R+jpSnaB0D+TpNokmpEjrkwQP1lBU1uvUz0s8u7y3LR 5Fh+7q0UUy/aXKPe3Ahm+SWO46nK/U11SFIGasx2DnETfMGQUVbeq+JTp+mBpSLB/INF tAvd5mVQKWBnACY+0rdmyJFUjWUtDgiw9T+nRsuzS9o+njas4jw2XdW6qfzy0GeDSTqv uoipGOIKoNrL6oWZgqXGCp9qIilYErr0QQwMNpC24KPCzTPF6G30PkHQkm0kAmuqInLZ 6XOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678725080; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=iC/9rxrLtt9j5YQSFIj4r+xqIhr4OIPVnE5VID9BZVo=; b=kvP3/EGIVBnNTtUSjn1adddbWsZpHZAxb1mJqH/aEA05ZG521e/9MVC0dwpvoUmz/y b7RlikY57+VtDhDTzNRDSLQZo0XGvLX543VreDEU88Ojr3Dz4oC2aWyNw8eFyrfs+6RB 4WMfFL4wI+g4WmJT0CBsRzr4sIUmFCgLsEcjbOzQvDORn91s+T7iSiBmRF49mnLxFe76 IERm0sV6mjH627eExuN4rlz+GQvJGA6GxL0oys0DG4jUUaMptVL+8INiErI38Fwz1ys5 q8fTGho+72xAlRyVrwO0jbSaHgyxRJ0Xnz69pE3h6GB6RldIJYC5jygI7H/nzGJJgsbJ B5Ow== X-Gm-Message-State: AO0yUKWv6nmgljzD96S5lT2RZZfK05gk/cRh/9UaxxIUl1Wcba4k+TPc L7Sm/CPApLfHL6br2vbrkadkXg== X-Google-Smtp-Source: AK7set+PlugTltwa4XqV6a/Qhb5TzyW/J1rlDrVJgoGyg5zLPsyfQOG83Zh0xrpRM/pyV7uWxPOa3A== X-Received: by 2002:a05:6402:7d3:b0:4b0:87ec:2b98 with SMTP id u19-20020a05640207d300b004b087ec2b98mr33964833edy.16.1678725080373; Mon, 13 Mar 2023 09:31:20 -0700 (PDT) Received: from [10.44.2.5] ([81.246.10.41]) by smtp.gmail.com with ESMTPSA id pw23-20020a17090720b700b008f398f25beesm3629029ejb.189.2023.03.13.09.31.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Mar 2023 09:31:20 -0700 (PDT) Message-ID: <284f332d-675c-6d7f-94f0-5d8a944ea075@tessares.net> Date: Mon, 13 Mar 2023 17:31:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH net v2 6/8] veth: take into account device reconfiguration for xdp_features flag Content-Language: en-GB To: Eric Dumazet Cc: Lorenzo Bianconi , netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com, saeedm@nvidia.com, leon@kernel.org, shayagr@amazon.com, akiyano@amazon.com, darinzon@amazon.com, sgoutham@marvell.com, lorenzo.bianconi@redhat.com, toke@redhat.com, teknoraver@meta.com, ttoukan.linux@gmail.com References: From: Matthieu Baerts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Eric, On 13/03/2023 16:53, Eric Dumazet wrote: > On Mon, Mar 13, 2023 at 8:50 AM Eric Dumazet wrote: >> >> On Mon, Mar 13, 2023 at 7:15 AM Matthieu Baerts >> wrote: >>> >>> Hi Lorenzo, >>> >>> On 09/03/2023 13:25, Lorenzo Bianconi wrote: >>>> Take into account tx/rx queues reconfiguration setting device >>>> xdp_features flag. Moreover consider NETIF_F_GRO flag in order to enable >>>> ndo_xdp_xmit callback. >>>> >>>> Fixes: 66c0e13ad236 ("drivers: net: turn on XDP features") >>>> Signed-off-by: Lorenzo Bianconi >>> >>> Thank you for the modification. >>> >>> Unfortunately, 'git bisect' just told me this modification is the origin >>> of a new WARN when using veth in a netns: >>> >>> >>> ###################### 8< ###################### >>> >>> ============================= >>> WARNING: suspicious RCU usage >>> 6.3.0-rc1-00144-g064d70527aaa #149 Not tainted >>> ----------------------------- >>> drivers/net/veth.c:1265 suspicious rcu_dereference_check() usage! >>> >>> other info that might help us debug this: >>> >> >> Same observation here, I am releasing a syzbot report with a repro. >> >> > > I guess a fix would be: > > diff --git a/drivers/net/veth.c b/drivers/net/veth.c > index 293dc3b2c84a6c1931e8df42cdcd5f2798004f3c..4da74ac27f9a2425d8d3f4ffcc93f453bd58e3a5 > 100644 > --- a/drivers/net/veth.c > +++ b/drivers/net/veth.c > @@ -1262,7 +1262,7 @@ static void veth_set_xdp_features(struct net_device *dev) > struct veth_priv *priv = netdev_priv(dev); > struct net_device *peer; > > - peer = rcu_dereference(priv->peer); > + peer = rtnl_dereference(priv->peer); > if (peer && peer->real_num_tx_queues <= dev->real_num_rx_queues) { > xdp_features_t val = NETDEV_XDP_ACT_BASIC | > NETDEV_XDP_ACT_REDIRECT | > Thank you for having looked! This patch avoids the warning on our side. Cheers, Matt -- Tessares | Belgium | Hybrid Access Solutions www.tessares.net