From patchwork Mon Apr 19 13:05:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 425199 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 A8DB9C43460 for ; Mon, 19 Apr 2021 13:18:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D4FD61403 for ; Mon, 19 Apr 2021 13:18:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238832AbhDSNSm (ORCPT ); Mon, 19 Apr 2021 09:18:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:54806 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239640AbhDSNQq (ORCPT ); Mon, 19 Apr 2021 09:16:46 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EFFD761246; Mon, 19 Apr 2021 13:14:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618838046; bh=QXEEnIMFb1usIywqSO4YVq+/fmvHo02LzcJsp6j+few=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C+DN3Yt8V7jBph6bo7CkicusnfZ8M2IM7SReSxA4uj6qlDqAlCoz9dsYZGYzmsPtL 62D5gU7SdtPwhq1yU3B8o0CjgoBRiTGIelPXPXsL/gCPjUs9xJ1rxBb9HtWwaldqH6 cnU/xibjlbUB35ipc6BQpbZ6prtIwLHqCiYz7eCs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tong Zhu , "David S. Miller" , Sasha Levin Subject: [PATCH 5.10 023/103] neighbour: Disregard DEAD dst in neigh_update Date: Mon, 19 Apr 2021 15:05:34 +0200 Message-Id: <20210419130528.590661430@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210419130527.791982064@linuxfoundation.org> References: <20210419130527.791982064@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Tong Zhu [ Upstream commit d47ec7a0a7271dda08932d6208e4ab65ab0c987c ] After a short network outage, the dst_entry is timed out and put in DST_OBSOLETE_DEAD. We are in this code because arp reply comes from this neighbour after network recovers. There is a potential race condition that dst_entry is still in DST_OBSOLETE_DEAD. With that, another neighbour lookup causes more harm than good. In best case all packets in arp_queue are lost. This is counterproductive to the original goal of finding a better path for those packets. I observed a worst case with 4.x kernel where a dst_entry in DST_OBSOLETE_DEAD state is associated with loopback net_device. It leads to an ethernet header with all zero addresses. A packet with all zero source MAC address is quite deadly with mac80211, ath9k and 802.11 block ack. It fails ieee80211_find_sta_by_ifaddr in ath9k (xmit.c). Ath9k flushes tx queue (ath_tx_complete_aggr). BAW (block ack window) is not updated. BAW logic is damaged and ath9k transmission is disabled. Signed-off-by: Tong Zhu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/neighbour.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 2fe4bbb6b80c..8339978d46ff 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1380,7 +1380,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, * we can reinject the packet there. */ n2 = NULL; - if (dst) { + if (dst && dst->obsolete != DST_OBSOLETE_DEAD) { n2 = dst_neigh_lookup_skb(dst, skb); if (n2) n1 = n2;