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=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,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 DB7B0C433E0 for ; Fri, 8 Jan 2021 02:37:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E847236F9 for ; Fri, 8 Jan 2021 02:37:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726919AbhAHCh3 (ORCPT ); Thu, 7 Jan 2021 21:37:29 -0500 Received: from smtp-fw-6002.amazon.com ([52.95.49.90]:61062 "EHLO smtp-fw-6002.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726844AbhAHCh2 (ORCPT ); Thu, 7 Jan 2021 21:37:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1610073448; x=1641609448; h=date:from:to:cc:message-id:references:mime-version: content-transfer-encoding:in-reply-to:subject; bh=my3Naolu1PChTdM9Bl0HiSg56oK/sbgUmZToPz64Yxo=; b=f32WMGvbM46PPI7fyPA3XrD6uqbC7Ogsr8r34V4mOAebfJvoz3TDnwpF JIGourGztRYd0utT/5baPnm0Kc7D5IL6AbMXiBlr7nmgnJVKtq9OYSqdG kj3o7gz8GmOa6bC2GVwYXn5AS3HQBE7T73yLfCxeGrAAmDxf8w5oQ9bSu k=; X-IronPort-AV: E=Sophos;i="5.79,330,1602547200"; d="scan'208";a="76128177" Subject: Re: [PATCH] neighbour: Disregard DEAD dst in neigh_update Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1d-98acfc19.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-out-6002.iad6.amazon.com with ESMTP; 08 Jan 2021 02:36:46 +0000 Received: from EX13MTAUEE001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-1d-98acfc19.us-east-1.amazon.com (Postfix) with ESMTPS id AD2E5A1F59; Fri, 8 Jan 2021 02:36:44 +0000 (UTC) Received: from EX13D06UEA002.ant.amazon.com (10.43.61.198) by EX13MTAUEE001.ant.amazon.com (10.43.62.226) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 8 Jan 2021 02:36:42 +0000 Received: from ucf43ac461c9a53.ant.amazon.com (10.43.161.68) by EX13D06UEA002.ant.amazon.com (10.43.61.198) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 8 Jan 2021 02:36:41 +0000 Date: Thu, 7 Jan 2021 21:36:37 -0500 From: Your Real Name To: David Miller CC: , , , , , Message-ID: <20210108023637.GA31904@ucf43ac461c9a53.ant.amazon.com> References: <20201230225415.GA490@ucf43ac461c9a53.ant.amazon.com> <20210105.160521.1279064249478522010.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210105.160521.1279064249478522010.davem@davemloft.net> User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [10.43.161.68] X-ClientProxiedBy: EX13D39UWA001.ant.amazon.com (10.43.160.54) To EX13D06UEA002.ant.amazon.com (10.43.61.198) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Jan 05, 2021 at 04:05:21PM -0800, David Miller wrote: > > > From: Tong Zhu > Date: Wed, 30 Dec 2020 17:54:23 -0500 > > > In 4.x kernel a dst in DST_OBSOLETE_DEAD state is associated > > with loopback net_device and leads to loopback neighbour. It > > leads to an ethernet header with all zero addresses. > > > > A very troubling case is working with mac80211 and ath9k. > > A packet with all zero source MAC address to mac80211 will > > eventually fail ieee80211_find_sta_by_ifaddr in ath9k (xmit.c). > > As result, ath9k flushes tx queue (ath_tx_complete_aggr) without > > updating baw (block ack window), damages baw logic and disables > > transmission. > > > > Signed-off-by: Tong Zhu > > Please repost with an appropriate Fixes: tag. > > Thanks. I had a second thought on this. This fix should go mainline too. This is a case we are sending out queued packets when arp reply from the neighbour comes in. With 5.x kernel, a dst in DST_OBSOLETE_DEAD state leads to dropping of this packet. It is not as bad as with 4.x kernel that may end up with an all-zero mac address packet out to ethernet or choking up ath9k when using block ack. Dropping the packet is still wrong. I’ll repost as a fix to mainline and target backport to 4.x LTS releases. Best regards