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 6CE36C04A68 for ; Wed, 27 Jul 2022 16:32:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237908AbiG0Qcl (ORCPT ); Wed, 27 Jul 2022 12:32:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236935AbiG0QcG (ORCPT ); Wed, 27 Jul 2022 12:32:06 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34A8552FDF; Wed, 27 Jul 2022 09:26:03 -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 17A21617EF; Wed, 27 Jul 2022 16:25:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EB66C433D7; Wed, 27 Jul 2022 16:25:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939139; bh=JHKJX3usD8Fg2C/Jq73gl9xKHcWlTsI1XEBlqA5VTpc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wfeQL5W1U3DrYoj6cw6706LWQsZTvTVTIem+5MoJ5JT2eYv0UbP4PexrfL5VpY63t w5gQmUxuhvc+1V4xphKGYJ5h/MsnP0lQStyxCBxtXJ8jjkBEOsTzAqvIOhYk70iG5F JGgAPMQghPTeQCxnSXzYN0CNAO7kyKKSLO7TH080= 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 4.19 27/62] tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts. Date: Wed, 27 Jul 2022 18:10:36 +0200 Message-Id: <20220727161005.271518041@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161004.175638564@linuxfoundation.org> References: <20220727161004.175638564@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 7c6f2a86ca590d5187a073d987e9599985fb1c7c ] While reading sysctl_tcp_thin_linear_timeouts, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 36e31b0af587 ("net: TCP thin linear timeouts") 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 e905fff09fea..84069db0423a 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -545,7 +545,7 @@ void tcp_retransmit_timer(struct sock *sk) * linear-timeout retransmissions into a black hole */ if (sk->sk_state == TCP_ESTABLISHED && - (tp->thin_lto || net->ipv4.sysctl_tcp_thin_linear_timeouts) && + (tp->thin_lto || READ_ONCE(net->ipv4.sysctl_tcp_thin_linear_timeouts)) && tcp_stream_is_thin(tp) && icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) { icsk->icsk_backoff = 0; -- 2.35.1