From patchwork Wed Jan 22 09:29:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 233370 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=-5.7 required=3.0 tests=DATE_IN_PAST_03_06, 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 897C7C33CB6 for ; Wed, 22 Jan 2020 13:30:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61301205F4 for ; Wed, 22 Jan 2020 13:30:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579699801; bh=AXzGzg7aB76QJhArJB3cCflXRp9u84Qf07aZ4biO7Uk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gbSJ62gPegrFYUszdcVmwvSW2ZyoD48QI9h38F+4GFi+I83xvW0x8GpLg4i+gvswQ JXGGi2hSZ2hg1d5HkfCkWk/xtMGN+/1GOV3SjYavjNHOzfFCw96pXWOKAjoEnhyEzF yuwi4rsoxrIMYKjJrtDckPR1nK8zYpIepTwCgnQQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730481AbgAVNYt (ORCPT ); Wed, 22 Jan 2020 08:24:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:44074 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730109AbgAVNYs (ORCPT ); Wed, 22 Jan 2020 08:24:48 -0500 Received: from localhost (unknown [84.241.205.26]) (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 9A23424688; Wed, 22 Jan 2020 13:24:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579699487; bh=AXzGzg7aB76QJhArJB3cCflXRp9u84Qf07aZ4biO7Uk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0jgSovNa2tRsD9uXPWp068r8BRPKqgMGKf1rHY8lCLyLEyvqcKudnYa0KRpd6fBbA 6JvJ4wnVk0ik68Jk3rQx7enW/d364Vmsfkbe2wCE7Yr5+1Yli3sba6dABkRbze3FE9 gyAO4TLUKySzsbktuAqe3hrWdHPQ0wiSVkswEeAE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ido Schimmel , Shalom Toledo , Jiri Pirko , "David S. Miller" Subject: [PATCH 5.4 161/222] mlxsw: spectrum: Do not modify cloned SKBs during xmit Date: Wed, 22 Jan 2020 10:29:07 +0100 Message-Id: <20200122092845.242283226@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200122092833.339495161@linuxfoundation.org> References: <20200122092833.339495161@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ido Schimmel commit 2da51ce75d86ab1f7770ac1391a9a1697ddaa60c upstream. The driver needs to prepend a Tx header to each packet it is transmitting. The header includes information such as the egress port and traffic class. The addition of the header requires the driver to modify the SKB's header and therefore it must not be shared. Otherwise, we risk hitting various race conditions. For example, when a packet is flooded (cloned) by the bridge driver to two switch ports swp1 and swp2: t0 - mlxsw_sp_port_xmit() is called for swp1. Tx header is prepended with swp1's port number t1 - mlxsw_sp_port_xmit() is called for swp2. Tx header is prepended with swp2's port number, overwriting swp1's port number t2 - The device processes data buffer from t0. Packet is transmitted via swp2 t3 - The device processes data buffer from t1. Packet is transmitted via swp2 Usually, the device is fast enough and transmits the packet before its Tx header is overwritten, but this is not the case in emulated environments. Fix this by making sure the SKB's header is writable by calling skb_cow_head(). Since the function ensures we have headroom to push the Tx header, the check further in the function can be removed. v2: * Use skb_cow_head() instead of skb_unshare() as suggested by Jakub * Remove unnecessary check regarding headroom Fixes: 56ade8fe3fe1 ("mlxsw: spectrum: Add initial support for Spectrum ASIC") Signed-off-by: Ido Schimmel Reported-by: Shalom Toledo Acked-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c @@ -812,23 +812,17 @@ static netdev_tx_t mlxsw_sp_port_xmit(st u64 len; int err; + if (skb_cow_head(skb, MLXSW_TXHDR_LEN)) { + this_cpu_inc(mlxsw_sp_port->pcpu_stats->tx_dropped); + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; + } + memset(skb->cb, 0, sizeof(struct mlxsw_skb_cb)); if (mlxsw_core_skb_transmit_busy(mlxsw_sp->core, &tx_info)) return NETDEV_TX_BUSY; - if (unlikely(skb_headroom(skb) < MLXSW_TXHDR_LEN)) { - struct sk_buff *skb_orig = skb; - - skb = skb_realloc_headroom(skb, MLXSW_TXHDR_LEN); - if (!skb) { - this_cpu_inc(mlxsw_sp_port->pcpu_stats->tx_dropped); - dev_kfree_skb_any(skb_orig); - return NETDEV_TX_OK; - } - dev_consume_skb_any(skb_orig); - } - if (eth_skb_pad(skb)) { this_cpu_inc(mlxsw_sp_port->pcpu_stats->tx_dropped); return NETDEV_TX_OK;