From patchwork Wed Jul 13 20:52:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12917110 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 1F8DDC433EF for ; Wed, 13 Jul 2022 20:56:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236851AbiGMU4B (ORCPT ); Wed, 13 Jul 2022 16:56:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50838 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235042AbiGMU4A (ORCPT ); Wed, 13 Jul 2022 16:56:00 -0400 Received: from smtp-fw-80007.amazon.com (smtp-fw-80007.amazon.com [99.78.197.218]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A91C136 for ; Wed, 13 Jul 2022 13:55:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1657745759; x=1689281759; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=G43/spNFR4cbDLDNX0n2e5bD7HjFrxbcJ0tqz6+2ho4=; b=i0x2iBTlFqHMThrbH9z7d+bfEpPv/GSxB4wwInNayNcljbHe14NWHqI0 2pqkUdOq4LrtLjuJDNmy8h4pUTwhqudWQX3t1hv8wS8/OfeqJB0IzmJO4 bpykhYo5UumMzZ3o2zw47Dr1FTYCitKk32XrP5zojL/xd1KQFG0GZ8JhC 4=; X-IronPort-AV: E=Sophos;i="5.92,269,1650931200"; d="scan'208";a="108049453" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-iad-1d-b48bc93b.us-east-1.amazon.com) ([10.25.36.214]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP; 13 Jul 2022 20:55:58 +0000 Received: from EX13MTAUWB001.ant.amazon.com (iad12-ws-svc-p26-lb9-vlan3.iad.amazon.com [10.40.163.38]) by email-inbound-relay-iad-1d-b48bc93b.us-east-1.amazon.com (Postfix) with ESMTPS id 38831C095B; Wed, 13 Jul 2022 20:55:55 +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; Wed, 13 Jul 2022 20:55:55 +0000 Received: from 88665a182662.ant.amazon.com.com (10.43.160.222) 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; Wed, 13 Jul 2022 20:55:53 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern CC: Kuniyuki Iwashima , Kuniyuki Iwashima , , Josh Hunt Subject: [PATCH v1 net 13/15] tcp: Fix a data-race around sysctl_tcp_mtu_probe_floor. Date: Wed, 13 Jul 2022 13:52:03 -0700 Message-ID: <20220713205205.15735-14-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220713205205.15735-1-kuniyu@amazon.com> References: <20220713205205.15735-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.160.222] X-ClientProxiedBy: EX13D29UWA002.ant.amazon.com (10.43.160.63) 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_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 --- CC: Josh Hunt --- 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 39107bb730b0..4f3b9ab222b6 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); }