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 2ED63C04A68 for ; Wed, 27 Jul 2022 16:40:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239380AbiG0QkM (ORCPT ); Wed, 27 Jul 2022 12:40:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239589AbiG0QjU (ORCPT ); Wed, 27 Jul 2022 12:39:20 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46F295005D; Wed, 27 Jul 2022 09:28:49 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 03ED1619FF; Wed, 27 Jul 2022 16:28:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E311C433D7; Wed, 27 Jul 2022 16:28:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939308; bh=c4SmNGB0sRDDaEoM2NEHpYGli5ogoDdY1dHqExV2Ru8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uCLi4cMD0G3t15CyYuMwqE0DfukGkpCiDO4rbOIuQmmN2X3ohA1ystlrq3iee+aYO OcCJjn89RuEjRd8G7gbDVFSvlacmuU6bdsYitSK5YQccyEDGOMZuu9XPwS70styOZv i+a+h6YPoLHba5bDaGo163hU8Qi6TWwC9+DznY44= 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 5.4 24/87] tcp: Fix a data-race around sysctl_tcp_mtu_probe_floor. Date: Wed, 27 Jul 2022 18:10:17 +0200 Message-Id: <20220727161010.006453319@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161008.993711844@linuxfoundation.org> References: <20220727161008.993711844@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 8e92d4423615a5257d0d871fc067aa561f597deb ] While reading sysctl_tcp_mtu_probe_floor, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: c04b79b6cfd7 ("tcp: add new tcp_mtu_probe_floor sysctl") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 0460c5deee3f..c48aeaef3ec7 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -172,7 +172,7 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) } else { mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1; mss = min(READ_ONCE(net->ipv4.sysctl_tcp_base_mss), mss); - mss = max(mss, net->ipv4.sysctl_tcp_mtu_probe_floor); + mss = max(mss, READ_ONCE(net->ipv4.sysctl_tcp_mtu_probe_floor)); mss = max(mss, READ_ONCE(net->ipv4.sysctl_tcp_min_snd_mss)); icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss); } -- 2.35.1