From patchwork Mon Jul 18 17:26:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12921514 X-Patchwork-Delegate: kuba@kernel.org 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 48439C43334 for ; Mon, 18 Jul 2022 17:29:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233707AbiGRR3V (ORCPT ); Mon, 18 Jul 2022 13:29:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233477AbiGRR3U (ORCPT ); Mon, 18 Jul 2022 13:29:20 -0400 Received: from smtp-fw-6002.amazon.com (smtp-fw-6002.amazon.com [52.95.49.90]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27BA264E8 for ; Mon, 18 Jul 2022 10:29:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1658165360; x=1689701360; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=cpT4xVqSZhSCvqRrHBX/KOAAtpvaN8BGS5RqhKLn/2E=; b=atZtJmxDj5eqXYeG3jApNP0HBvKM4M30zBY+pHAr11bzYIWUSUI01hfv KP0vaz0bNEJ4WO6njg4XC0VOhVoKxtx4Umge+8GujrzZ7ICR4qEWprI9X zCtRa9GTS2enfbSBlJwCIS58fkhGvywwjY8uKjsD7/jIqJgYk13moOxO+ I=; X-IronPort-AV: E=Sophos;i="5.92,281,1650931200"; d="scan'208";a="222975021" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-pdx-2b-02ee77e7.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-6002.iad6.amazon.com with ESMTP; 18 Jul 2022 17:29:18 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-pdx-2b-02ee77e7.us-west-2.amazon.com (Postfix) with ESMTPS id 6014143F30; Mon, 18 Jul 2022 17:29:18 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Mon, 18 Jul 2022 17:29:17 +0000 Received: from 88665a182662.ant.amazon.com (10.43.160.159) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.9; Mon, 18 Jul 2022 17:29:14 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern CC: Kuniyuki Iwashima , Kuniyuki Iwashima , , Andreas Petlund Subject: [PATCH v1 net 09/15] tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts. Date: Mon, 18 Jul 2022 10:26:47 -0700 Message-ID: <20220718172653.22111-10-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220718172653.22111-1-kuniyu@amazon.com> References: <20220718172653.22111-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.160.159] X-ClientProxiedBy: EX13D04UWA004.ant.amazon.com (10.43.160.234) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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 --- CC: Andreas Petlund --- 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 ec5277becc6a..50bba370486e 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -578,7 +578,7 @@ 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;