From patchwork Thu Jan 2 22:07:46 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: 234544 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 ECD0DC3276C for ; Thu, 2 Jan 2020 22:52:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8CCA20866 for ; Thu, 2 Jan 2020 22:52:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578005577; bh=QCKbD5lsG3y8EzqeBjyyj/2nvanhz5ueWZviiPgGRrQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yVjPbXTlIlEfIcg2ALrY3JhhQTJDP8HFCkP10tyK2SUlQS2Io3R99j8cfpwSba+/t pGZf/OAa2129NznYLX5Z3+xnOQen/WPdmud5glER521SJk11ChhGoulbO6w3gY5UtF TSed62w1UCCUy94kEDIEAa6KtM9pCLNzIxzr1V7Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727815AbgABWWV (ORCPT ); Thu, 2 Jan 2020 17:22:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:42752 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729131AbgABWWU (ORCPT ); Thu, 2 Jan 2020 17:22:20 -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 AB75321D7D; Thu, 2 Jan 2020 22:22:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578003740; bh=QCKbD5lsG3y8EzqeBjyyj/2nvanhz5ueWZviiPgGRrQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ViRX9ZtQbRDdVCmKFZCeA6oOxUj9ZMC/7UFLU1qXnGGxcizZ4/UXYxOss0ljht4Py 42aArmlIqJex4N4W2aliOtD6o+10Ln7hIvGDkKGrymQswnyfamwiypnDIOCVq7F3UH B/9PYr6YhUCjCApraTTp/VwhuGQX/6dak0YELhRA= 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 4.19 094/114] tcp: Fix highest_sack and highest_sack_seq Date: Thu, 2 Jan 2020 23:07:46 +0100 Message-Id: <20200102220038.629285760@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102220029.183913184@linuxfoundation.org> References: <20200102220029.183913184@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 @@ -60,6 +60,9 @@ 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);