From patchwork Thu Jan 2 22:07:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 234779 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=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 33E90C3276D for ; Thu, 2 Jan 2020 22:17:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2E9E21582 for ; Thu, 2 Jan 2020 22:17:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578003429; bh=U5OhwoZMXsTMWEiyi7YTEg3+XjubgFHhT59/nUqI7cM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pdqQPoSADfNd2vLxkcUD0fkCz6K9ttGIzWh3OrcqN9MmJDPnAGytvTozYOi7WHp3Q dUt+FZHGE2tMm0eAc0iC3jlzT5Ad+5qIDMqP6s9vWr0ghqbeEA4Dx0CNqd/Xs8LudL 0AbFG96+9weSFLn7wqO7JvRXRhrxFr7qZBNHsSRE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728085AbgABWRH (ORCPT ); Thu, 2 Jan 2020 17:17:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:59384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727374AbgABWRG (ORCPT ); Thu, 2 Jan 2020 17:17:06 -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 3D60B22314; Thu, 2 Jan 2020 22:17:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578003425; bh=U5OhwoZMXsTMWEiyi7YTEg3+XjubgFHhT59/nUqI7cM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=linFcp4POg49N14wNpQVjQpqr0r9S5VfB515oMRJuAAyjKPa31ZEXW+bRsOSD3FNV UT/GuOkrOoC/27btqfiKi1wgKXHtswANz6csO/hPOL3TM81L7PdcO/Q3qNKwn9qzKa H+Y+l0OoUlG3uH/Mx1diws/Y+5d08MvMRx8T+D7c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Cambda Zhu , Eric Dumazet , "David S. Miller" Subject: [PATCH 5.4 156/191] tcp: Fix highest_sack and highest_sack_seq Date: Thu, 2 Jan 2020 23:07:18 +0100 Message-Id: <20200102215846.141998616@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102215829.911231638@linuxfoundation.org> References: <20200102215829.911231638@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: Cambda Zhu [ Upstream commit 853697504de043ff0bfd815bd3a64de1dce73dc7 ] >From commit 50895b9de1d3 ("tcp: highest_sack fix"), the logic about setting tp->highest_sack to the head of the send queue was removed. Of course the logic is error prone, but it is logical. Before we remove the pointer to the highest sack skb and use the seq instead, we need to set tp->highest_sack to NULL when there is no skb after the last sack, and then replace NULL with the real skb when new skb inserted into the rtx queue, because the NULL means the highest sack seq is tp->snd_nxt. If tp->highest_sack is NULL and new data sent, the next ACK with sack option will increase tp->reordering unexpectedly. This patch sets tp->highest_sack to the tail of the rtx queue if it's NULL and new data is sent. The patch keeps the rule that the highest_sack can only be maintained by sack processing, except for this only case. Fixes: 50895b9de1d3 ("tcp: highest_sack fix") Signed-off-by: Cambda Zhu Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_output.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -72,6 +72,9 @@ static void tcp_event_new_data_sent(stru __skb_unlink(skb, &sk->sk_write_queue); tcp_rbtree_insert(&sk->tcp_rtx_queue, skb); + if (tp->highest_sack == NULL) + tp->highest_sack = skb; + tp->packets_out += tcp_skb_pcount(skb); if (!prior_packets || icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) tcp_rearm_rto(sk);