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[23.128.96.18]) by mx.google.com with ESMTP id h9si29445133edw.501.2021.07.22.09.54.46; Thu, 22 Jul 2021 09:55:10 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b="c/m3on6p"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235077AbhGVQMn (ORCPT + 99 others); Thu, 22 Jul 2021 12:12:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:47280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234220AbhGVQI7 (ORCPT ); Thu, 22 Jul 2021 12:08:59 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2A82161DC7; Thu, 22 Jul 2021 16:48:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626972524; bh=ThXlEs92FBXVCti8cyyCvp0sAcHbzL4TpZlBG5kLZms=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c/m3on6pubRkUoawjeqS67icGX1DoSAvpP4ij57nNIFEcEG/WiO0zaCTqjKvBy0XK T5ipBbtXeH49Wu+39Vnyyzt/cfN7m/PJ9EPkVdkQ7+mEvYGRSgOYadcKq+vhat//rQ 9Vy9+xj8jzUVXQIWEoP6QNpcNABaiwWKYMc9gXpM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , "David S. Miller" Subject: [PATCH 5.13 144/156] tcp: annotate data races around tp->mtu_info Date: Thu, 22 Jul 2021 18:31:59 +0200 Message-Id: <20210722155633.000585204@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210722155628.371356843@linuxfoundation.org> References: <20210722155628.371356843@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: Eric Dumazet commit 561022acb1ce62e50f7a8258687a21b84282a4cb upstream. While tp->mtu_info is read while socket is owned, the write sides happen from err handlers (tcp_v[46]_mtu_reduced) which only own the socket spinlock. Fixes: 563d34d05786 ("tcp: dont drop MTU reduction indications") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_ipv4.c | 4 ++-- net/ipv6/tcp_ipv6.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -342,7 +342,7 @@ void tcp_v4_mtu_reduced(struct sock *sk) if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) return; - mtu = tcp_sk(sk)->mtu_info; + mtu = READ_ONCE(tcp_sk(sk)->mtu_info); dst = inet_csk_update_pmtu(sk, mtu); if (!dst) return; @@ -546,7 +546,7 @@ int tcp_v4_err(struct sk_buff *skb, u32 if (sk->sk_state == TCP_LISTEN) goto out; - tp->mtu_info = info; + WRITE_ONCE(tp->mtu_info, info); if (!sock_owned_by_user(sk)) { tcp_v4_mtu_reduced(sk); } else { --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -352,7 +352,7 @@ static void tcp_v6_mtu_reduced(struct so if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) return; - dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info); + dst = inet6_csk_update_pmtu(sk, READ_ONCE(tcp_sk(sk)->mtu_info)); if (!dst) return; @@ -443,7 +443,7 @@ static int tcp_v6_err(struct sk_buff *sk if (!ip6_sk_accept_pmtu(sk)) goto out; - tp->mtu_info = ntohl(info); + WRITE_ONCE(tp->mtu_info, ntohl(info)); if (!sock_owned_by_user(sk)) tcp_v6_mtu_reduced(sk); else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,