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 9C61CC04A68 for ; Wed, 27 Jul 2022 16:45:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240348AbiG0Qpl (ORCPT ); Wed, 27 Jul 2022 12:45:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240462AbiG0Qo2 (ORCPT ); Wed, 27 Jul 2022 12:44:28 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2260651A3B; Wed, 27 Jul 2022 09:31:11 -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 9E34BB821BE; Wed, 27 Jul 2022 16:31:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF398C433D6; Wed, 27 Jul 2022 16:31:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939468; bh=xDorO/C3ElwiBLmXQmAIT9qsfde0KxyKSDyPqNa8N5s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AnJpSbq928Qa3d6wmMtYjjFoOYM2/Fdabp3EQzPGn/bfJ6fmbkfqaNnk7jG29LrAz E6GiUtJlnPzs3pIDJCerWmtUrAIlC2MVqw2LtoBQaD7myUZ8DOSnE8y392TyYPa4wS ollHe8Iug/GFG8dWgqtxKWvGqCVot0CjJcBSIhv0= 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 49/87] tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts. Date: Wed, 27 Jul 2022 18:10:42 +0200 Message-Id: <20220727161011.044246395@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 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 26da44e196ed..a0107eb02ae4 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -569,7 +569,7 @@ 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