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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E009C433EF for ; Tue, 19 Jul 2022 13:02:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242590AbiGSNCh (ORCPT ); Tue, 19 Jul 2022 09:02:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242919AbiGSM7t (ORCPT ); Tue, 19 Jul 2022 08:59:49 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EBA4E4BD06; Tue, 19 Jul 2022 05:25:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 13D58B81B82; Tue, 19 Jul 2022 12:25:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6AF8DC341C6; Tue, 19 Jul 2022 12:25:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658233515; bh=LNbB8tIV6AgkH04KAZ85y76xz1DHDWBXK4uA1vgSrE4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y5JddwXX3gNtKscOAmEMCC2B3eg/AysmDtjAhOd66koG5S1rB3b0p+5SslRWpZ1lQ mrSImOgMxDAwndMQ++2kOIDb87zQlf6Yyib+izIAxnwXW5lakDoUsb5TEmM2DmF6sO eXsneFcFXfv/lF8cgwn1ksgv0GXa6wuCiEcJojIk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 5.18 121/231] tcp: Fix a data-race around sysctl_tcp_ecn_fallback. Date: Tue, 19 Jul 2022 13:53:26 +0200 Message-Id: <20220719114724.628158175@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220719114714.247441733@linuxfoundation.org> References: <20220719114714.247441733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuniyuki Iwashima [ Upstream commit 12b8d9ca7e678abc48195294494f1815b555d658 ] While reading sysctl_tcp_ecn_fallback, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 492135557dc0 ("tcp: add rfc3168, section 6.1.1.1. fallback") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/sysctl_net_ipv4.c | 2 ++ net/ipv4/tcp_output.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 11add5214713..ffe0264a51b8 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -689,6 +689,8 @@ static struct ctl_table ipv4_net_table[] = { .maxlen = sizeof(u8), .mode = 0644, .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, }, { .procname = "ip_dynaddr", diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 9eefe7f6370f..34249469e361 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -346,7 +346,7 @@ static void tcp_ecn_send_syn(struct sock *sk, struct sk_buff *skb) static void tcp_ecn_clear_syn(struct sock *sk, struct sk_buff *skb) { - if (sock_net(sk)->ipv4.sysctl_tcp_ecn_fallback) + if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_fallback)) /* tp->ecn_flags are cleared at a later point in time when * SYN ACK is ultimatively being received. */ -- 2.35.1