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 29DE6C25B06 for ; Mon, 1 Aug 2022 11:49:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231714AbiHALtM (ORCPT ); Mon, 1 Aug 2022 07:49:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231609AbiHALsr (ORCPT ); Mon, 1 Aug 2022 07:48:47 -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 D2E483C8D9; Mon, 1 Aug 2022 04:48:24 -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 1BED2612D5; Mon, 1 Aug 2022 11:48:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2BF93C433C1; Mon, 1 Aug 2022 11:48:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1659354503; bh=C87C7EzLl4tWVgrvdxffYag5TQAHIvH812FsT8eBZRQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JS+wuthP94xyVCchaJjdUxeua7kTNrNu9TtAULkRwUG8keUYAOWGnKViDwJ17FBHw XcnrJ4W+ZmjEhDCvuWZYDy8oTHn3D4JZn0NqDswH4ZrPxdc78nBYfAi2E4MilIJ3YE aMfQ1m/FigSq8GWNjMgtdIYudxoIivxQ9geiodRo= 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 19/34] tcp: Fix a data-race around sysctl_tcp_min_rtt_wlen. Date: Mon, 1 Aug 2022 13:46:59 +0200 Message-Id: <20220801114128.774532066@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220801114128.025615151@linuxfoundation.org> References: <20220801114128.025615151@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 1330ffacd05fc9ac4159d19286ce119e22450ed2 ] While reading sysctl_tcp_min_rtt_wlen, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: f672258391b4 ("tcp: track min RTT using windowed min-filter") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a8d8ff488281..b760ad0b16d9 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2914,7 +2914,7 @@ static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una, static void tcp_update_rtt_min(struct sock *sk, u32 rtt_us, const int flag) { - u32 wlen = sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen * HZ; + u32 wlen = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_min_rtt_wlen) * HZ; struct tcp_sock *tp = tcp_sk(sk); if ((flag & FLAG_ACK_MAYBE_DELAYED) && rtt_us > tcp_min_rtt(tp)) { -- 2.35.1