From patchwork Fri Jul 15 17:17:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12919498 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 BFEB3C43334 for ; Fri, 15 Jul 2022 17:20:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235315AbiGORUC (ORCPT ); Fri, 15 Jul 2022 13:20:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233509AbiGORUB (ORCPT ); Fri, 15 Jul 2022 13:20:01 -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 7B4D46C129 for ; Fri, 15 Jul 2022 10:20:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1657905601; x=1689441601; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=+rRR3BHOx4/irfYDHgKxn278I25c5ki6gnfK2Fq/Na4=; b=mqcjOHI9jbkfdmG3z1WGz0o5XFDqfoUU196I8ETyRAvzhaOCIkm7hbVT Ug10/83DN+vBl3vOYvKUunnZv+co/KAPholt/pigKcekY4QrRDJ7TJnnI dblfdKQm5iz5OEKDrdN5lHDcI/7UtxDAZ4FhDHgzi3ifH/oi3kJKmpK3h E=; X-IronPort-AV: E=Sophos;i="5.92,274,1650931200"; d="scan'208";a="108935386" Received: from pdx4-co-svc-p1-lb2-vlan3.amazon.com (HELO email-inbound-relay-pdx-2c-51ba86d8.us-west-2.amazon.com) ([10.25.36.214]) by smtp-border-fw-80007.pdx80.corp.amazon.com with ESMTP; 15 Jul 2022 17:19:45 +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-2c-51ba86d8.us-west-2.amazon.com (Postfix) with ESMTPS id 04CC383B0E; Fri, 15 Jul 2022 17:19:45 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.207) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Fri, 15 Jul 2022 17:19:44 +0000 Received: from 88665a182662.ant.amazon.com (10.43.162.124) 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; Fri, 15 Jul 2022 17:19:41 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern CC: Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v1 net 06/15] tcp: Fix data-races around sysctl_tcp_syn(ack)?_retries. Date: Fri, 15 Jul 2022 10:17:46 -0700 Message-ID: <20220715171755.38497-7-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220715171755.38497-1-kuniyu@amazon.com> References: <20220715171755.38497-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.162.124] X-ClientProxiedBy: EX13D31UWA003.ant.amazon.com (10.43.160.130) 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_syn(ack)?_retries, they can be changed concurrently. Thus, we need to add READ_ONCE() to their readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima --- net/ipv4/inet_connection_sock.c | 3 ++- net/ipv4/tcp.c | 3 ++- net/ipv4/tcp_timer.c | 10 +++++++--- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index 2c44556af452..eb31c7158b39 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -833,7 +833,8 @@ static void reqsk_timer_handler(struct timer_list *t) icsk = inet_csk(sk_listener); net = sock_net(sk_listener); - max_syn_ack_retries = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_synack_retries; + max_syn_ack_retries = icsk->icsk_syn_retries ? : + READ_ONCE(net->ipv4.sysctl_tcp_synack_retries); /* Normally all the openreqs are young and become mature * (i.e. converted to established socket) for first timeout. * If synack was not acknowledged for 1 second, it means diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 2222dfdde316..19ce08c9fbdc 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3967,7 +3967,8 @@ static int do_tcp_getsockopt(struct sock *sk, int level, val = keepalive_probes(tp); break; case TCP_SYNCNT: - val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; + val = icsk->icsk_syn_retries ? : + READ_ONCE(net->ipv4.sysctl_tcp_syn_retries); break; case TCP_LINGER2: val = tp->linger2; diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index 4f3b9ab222b6..a234704e8163 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -239,7 +239,8 @@ static int tcp_write_timeout(struct sock *sk) if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { if (icsk->icsk_retransmits) __dst_negative_advice(sk); - retry_until = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries; + retry_until = icsk->icsk_syn_retries ? : + READ_ONCE(net->ipv4.sysctl_tcp_syn_retries); expired = icsk->icsk_retransmits >= retry_until; } else { if (retransmits_timed_out(sk, net->ipv4.sysctl_tcp_retries1, 0)) { @@ -406,12 +407,15 @@ abort: tcp_write_err(sk); static void tcp_fastopen_synack_timer(struct sock *sk, struct request_sock *req) { struct inet_connection_sock *icsk = inet_csk(sk); - int max_retries = icsk->icsk_syn_retries ? : - sock_net(sk)->ipv4.sysctl_tcp_synack_retries + 1; /* add one more retry for fastopen */ struct tcp_sock *tp = tcp_sk(sk); + int max_retries; req->rsk_ops->syn_ack_timeout(req); + /* add one more retry for fastopen */ + max_retries = icsk->icsk_syn_retries ? : + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_synack_retries) + 1; + if (req->num_timeout >= max_retries) { tcp_write_err(sk); return;