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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 1FA8BC2D0BF for ; Tue, 17 Dec 2019 20:17:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E561921D7D for ; Tue, 17 Dec 2019 20:17:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576613869; bh=kU/g2d6zDLkg2lDHlxUGE+KJKoOB9BR28nfUxunsxVo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZcpokKR8Gcbyd3hB55/P+hEOgakLq6xnSlLBa/RKHuAMtR2uVMjp8d7KT3+YcDOkE GmNuPTyGdJERB7xkcINesn7rdEbtYj+nZc5I2yugP1jwPBFztz7B5VKNmieGnTNrY2 vohieRgxtiM3ky4sA9C3eDOoYBvo1cJGoWzO0AhU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727804AbfLQURo (ORCPT ); Tue, 17 Dec 2019 15:17:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:41822 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728793AbfLQURV (ORCPT ); Tue, 17 Dec 2019 15:17:21 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9F0D0206D8; Tue, 17 Dec 2019 20:17:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576613840; bh=kU/g2d6zDLkg2lDHlxUGE+KJKoOB9BR28nfUxunsxVo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lyOjwhqjPLYV2DyD+qHPVlIZb8aQyxYJkBOpgXImLIQu41Us7vRegN8i99olzcmYD fCzObSLf7VbiliuV8pSoXHWSogv4A9oUutYeK6eRpR8j4sm1e1/ONEnQpRTa5vMyTR yjrkGbXp/vXTlGojzDaB+GOyFoRSVlUFZuK53w7A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Lobakin , Florian Fainelli , "David S. Miller" Subject: [PATCH 5.3 04/25] net: dsa: fix flow dissection on Tx path Date: Tue, 17 Dec 2019 21:16:03 +0100 Message-Id: <20191217200905.191919415@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191217200903.179327435@linuxfoundation.org> References: <20191217200903.179327435@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Alexander Lobakin [ Upstream commit 8bef0af09a5415df761b04fa487a6c34acae74bc ] Commit 43e665287f93 ("net-next: dsa: fix flow dissection") added an ability to override protocol and network offset during flow dissection for DSA-enabled devices (i.e. controllers shipped as switch CPU ports) in order to fix skb hashing for RPS on Rx path. However, skb_hash() and added part of code can be invoked not only on Rx, but also on Tx path if we have a multi-queued device and: - kernel is running on UP system or - XPS is not configured. The call stack in this two cases will be like: dev_queue_xmit() -> __dev_queue_xmit() -> netdev_core_pick_tx() -> netdev_pick_tx() -> skb_tx_hash() -> skb_get_hash(). The problem is that skbs queued for Tx have both network offset and correct protocol already set up even after inserting a CPU tag by DSA tagger, so calling tag_ops->flow_dissect() on this path actually only breaks flow dissection and hashing. This can be observed by adding debug prints just before and right after tag_ops->flow_dissect() call to the related block of code: Before the patch: Rx path (RPS): [ 19.240001] Rx: proto: 0x00f8, nhoff: 0 /* ETH_P_XDSA */ [ 19.244271] tag_ops->flow_dissect() [ 19.247811] Rx: proto: 0x0800, nhoff: 8 /* ETH_P_IP */ [ 19.215435] Rx: proto: 0x00f8, nhoff: 0 /* ETH_P_XDSA */ [ 19.219746] tag_ops->flow_dissect() [ 19.223241] Rx: proto: 0x0806, nhoff: 8 /* ETH_P_ARP */ [ 18.654057] Rx: proto: 0x00f8, nhoff: 0 /* ETH_P_XDSA */ [ 18.658332] tag_ops->flow_dissect() [ 18.661826] Rx: proto: 0x8100, nhoff: 8 /* ETH_P_8021Q */ Tx path (UP system): [ 18.759560] Tx: proto: 0x0800, nhoff: 26 /* ETH_P_IP */ [ 18.763933] tag_ops->flow_dissect() [ 18.767485] Tx: proto: 0x920b, nhoff: 34 /* junk */ [ 22.800020] Tx: proto: 0x0806, nhoff: 26 /* ETH_P_ARP */ [ 22.804392] tag_ops->flow_dissect() [ 22.807921] Tx: proto: 0x920b, nhoff: 34 /* junk */ [ 16.898342] Tx: proto: 0x86dd, nhoff: 26 /* ETH_P_IPV6 */ [ 16.902705] tag_ops->flow_dissect() [ 16.906227] Tx: proto: 0x920b, nhoff: 34 /* junk */ After: Rx path (RPS): [ 16.520993] Rx: proto: 0x00f8, nhoff: 0 /* ETH_P_XDSA */ [ 16.525260] tag_ops->flow_dissect() [ 16.528808] Rx: proto: 0x0800, nhoff: 8 /* ETH_P_IP */ [ 15.484807] Rx: proto: 0x00f8, nhoff: 0 /* ETH_P_XDSA */ [ 15.490417] tag_ops->flow_dissect() [ 15.495223] Rx: proto: 0x0806, nhoff: 8 /* ETH_P_ARP */ [ 17.134621] Rx: proto: 0x00f8, nhoff: 0 /* ETH_P_XDSA */ [ 17.138895] tag_ops->flow_dissect() [ 17.142388] Rx: proto: 0x8100, nhoff: 8 /* ETH_P_8021Q */ Tx path (UP system): [ 15.499558] Tx: proto: 0x0800, nhoff: 26 /* ETH_P_IP */ [ 20.664689] Tx: proto: 0x0806, nhoff: 26 /* ETH_P_ARP */ [ 18.565782] Tx: proto: 0x86dd, nhoff: 26 /* ETH_P_IPV6 */ In order to fix that we can add the check 'proto == htons(ETH_P_XDSA)' to prevent code from calling tag_ops->flow_dissect() on Tx. I also decided to initialize 'offset' variable so tagger callbacks can now safely leave it untouched without provoking a chaos. Fixes: 43e665287f93 ("net-next: dsa: fix flow dissection") Signed-off-by: Alexander Lobakin Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/flow_dissector.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -853,9 +853,10 @@ bool __skb_flow_dissect(const struct net nhoff = skb_network_offset(skb); hlen = skb_headlen(skb); #if IS_ENABLED(CONFIG_NET_DSA) - if (unlikely(skb->dev && netdev_uses_dsa(skb->dev))) { + if (unlikely(skb->dev && netdev_uses_dsa(skb->dev) && + proto == htons(ETH_P_XDSA))) { const struct dsa_device_ops *ops; - int offset; + int offset = 0; ops = skb->dev->dsa_ptr->tag_ops; if (ops->flow_dissect &&