From patchwork Fri Jul 15 17:17:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12919501 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF1ACC43334 for ; Fri, 15 Jul 2022 17:20:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235609AbiGORUf (ORCPT ); Fri, 15 Jul 2022 13:20:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234994AbiGORUe (ORCPT ); Fri, 15 Jul 2022 13:20:34 -0400 Received: from smtp-fw-33001.amazon.com (smtp-fw-33001.amazon.com [207.171.190.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7671F286CA for ; Fri, 15 Jul 2022 10:20:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1657905633; x=1689441633; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Gq8zQD5mTSTxbCBm8w74NWjjXruOWEtq62jUPC0L1Ig=; b=LTBzNHNdqvH0K8QruDVL0glwGnUFLCSf3oO3uLJiOBv9dMMAIyOHBLi+ vUilfUoW4+sA3qpMJpG4Vj5ZXwUwpQpM80CZmuekvpoRHZf5CkzIpOw1i 4xUNYjzX6HDC6jFX98gwhyiGncvuO6UvTEoCTKutsyUuuePadIM1kMY3D U=; X-IronPort-AV: E=Sophos;i="5.92,274,1650931200"; d="scan'208";a="210370172" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-pdx-2b-718d0906.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-33001.sea14.amazon.com with ESMTP; 15 Jul 2022 17:20:31 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-pdx-2b-718d0906.us-west-2.amazon.com (Postfix) with ESMTPS id 58A273E018F; Fri, 15 Jul 2022 17:20:30 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.207) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Fri, 15 Jul 2022 17:20:29 +0000 Received: from 88665a182662.ant.amazon.com (10.43.162.124) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.9; Fri, 15 Jul 2022 17:20:27 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern CC: Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v1 net 09/15] tcp: Fix data-races around sysctl_tcp_reordering. Date: Fri, 15 Jul 2022 10:17:49 -0700 Message-ID: <20220715171755.38497-10-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220715171755.38497-1-kuniyu@amazon.com> References: <20220715171755.38497-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.162.124] X-ClientProxiedBy: EX13D31UWA003.ant.amazon.com (10.43.160.130) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org While reading sysctl_tcp_reordering, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima --- net/ipv4/tcp.c | 2 +- net/ipv4/tcp_input.c | 10 +++++++--- net/ipv4/tcp_metrics.c | 3 ++- 3 files changed, 10 insertions(+), 5 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 19ce08c9fbdc..b3632fa5df07 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -441,7 +441,7 @@ void tcp_init_sock(struct sock *sk) tp->snd_cwnd_clamp = ~0; tp->mss_cache = TCP_MSS_DEFAULT; - tp->reordering = sock_net(sk)->ipv4.sysctl_tcp_reordering; + tp->reordering = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reordering); tcp_assign_congestion_control(sk); tp->tsoffset = 0; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 8271eaad887b..de4ccd173c7f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2139,6 +2139,7 @@ void tcp_enter_loss(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); struct net *net = sock_net(sk); bool new_recovery = icsk->icsk_ca_state < TCP_CA_Recovery; + u8 reordering; tcp_timeout_mark_lost(sk); @@ -2159,10 +2160,12 @@ void tcp_enter_loss(struct sock *sk) /* Timeout in disordered state after receiving substantial DUPACKs * suggests that the degree of reordering is over-estimated. */ + reordering = READ_ONCE(net->ipv4.sysctl_tcp_reordering); if (icsk->icsk_ca_state <= TCP_CA_Disorder && - tp->sacked_out >= net->ipv4.sysctl_tcp_reordering) + tp->sacked_out >= reordering) tp->reordering = min_t(unsigned int, tp->reordering, - net->ipv4.sysctl_tcp_reordering); + reordering); + tcp_set_ca_state(sk, TCP_CA_Loss); tp->high_seq = tp->snd_nxt; tcp_ecn_queue_cwr(tp); @@ -3464,7 +3467,8 @@ static inline bool tcp_may_raise_cwnd(const struct sock *sk, const int flag) * new SACK or ECE mark may first advance cwnd here and later reduce * cwnd in tcp_fastretrans_alert() based on more states. */ - if (tcp_sk(sk)->reordering > sock_net(sk)->ipv4.sysctl_tcp_reordering) + if (tcp_sk(sk)->reordering > + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_reordering)) return flag & FLAG_FORWARD_PROGRESS; return flag & FLAG_DATA_ACKED; diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 7029b0e98edb..a501150deaa3 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -428,7 +428,8 @@ void tcp_update_metrics(struct sock *sk) if (!tcp_metric_locked(tm, TCP_METRIC_REORDERING)) { val = tcp_metric_get(tm, TCP_METRIC_REORDERING); if (val < tp->reordering && - tp->reordering != net->ipv4.sysctl_tcp_reordering) + tp->reordering != + READ_ONCE(net->ipv4.sysctl_tcp_reordering)) tcp_metric_set(tm, TCP_METRIC_REORDERING, tp->reordering); }