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 1DFD9C001DE for ; Tue, 25 Jul 2023 11:11:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234134AbjGYLLa (ORCPT ); Tue, 25 Jul 2023 07:11:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234047AbjGYLLQ (ORCPT ); Tue, 25 Jul 2023 07:11:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3FD1030E7 for ; Tue, 25 Jul 2023 04:10:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D18906166E for ; Tue, 25 Jul 2023 11:10:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE200C433C9; Tue, 25 Jul 2023 11:10:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690283431; bh=kDVWU1bukJUFpTWOTUMFs3F3j5E32bX3/jpfZ6vp6ow=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NoDRydIoqo1IAWQe2+u970fJSxtRR8NYcwIhxrwrp7D8qw3sfPuwlulXXc60aiWU1 UFCIaJn50hWnFkINz0o1rkQbo+yJlIHFmh2GGSmf9HEQUYtuHih2n1sLiqkSziNMnK 6bP4ba+bWisOlCgBFvPw+ODqX4KJcHQuZS4AtWeM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 74/78] tcp: annotate data-races around fastopenq.max_qlen Date: Tue, 25 Jul 2023 12:47:05 +0200 Message-ID: <20230725104454.140256122@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725104451.275227789@linuxfoundation.org> References: <20230725104451.275227789@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit 70f360dd7042cb843635ece9d28335a4addff9eb ] This field can be read locklessly. Fixes: 1536e2857bd3 ("tcp: Add a TCP_FASTOPEN socket option to get a max backlog on its listner") Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/r/20230719212857.3943972-12-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/linux/tcp.h | 2 +- net/ipv4/tcp.c | 2 +- net/ipv4/tcp_fastopen.c | 6 ++++-- 3 files changed, 6 insertions(+), 4 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index a7ebadf83c681..07a84ae6bf81c 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -473,7 +473,7 @@ static inline void fastopen_queue_tune(struct sock *sk, int backlog) struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; int somaxconn = READ_ONCE(sock_net(sk)->core.sysctl_somaxconn); - queue->fastopenq.max_qlen = min_t(unsigned int, backlog, somaxconn); + WRITE_ONCE(queue->fastopenq.max_qlen, min_t(unsigned int, backlog, somaxconn)); } static inline void tcp_move_syn(struct tcp_sock *tp, diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index cf486d75da836..a91cf000bb61b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4142,7 +4142,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level, break; case TCP_FASTOPEN: - val = icsk->icsk_accept_queue.fastopenq.max_qlen; + val = READ_ONCE(icsk->icsk_accept_queue.fastopenq.max_qlen); break; case TCP_FASTOPEN_CONNECT: diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index 6e0a8ef5e816f..e9b5d6f10c56d 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -301,6 +301,7 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk, static bool tcp_fastopen_queue_check(struct sock *sk) { struct fastopen_queue *fastopenq; + int max_qlen; /* Make sure the listener has enabled fastopen, and we don't * exceed the max # of pending TFO requests allowed before trying @@ -313,10 +314,11 @@ static bool tcp_fastopen_queue_check(struct sock *sk) * temporarily vs a server not supporting Fast Open at all. */ fastopenq = &inet_csk(sk)->icsk_accept_queue.fastopenq; - if (fastopenq->max_qlen == 0) + max_qlen = READ_ONCE(fastopenq->max_qlen); + if (max_qlen == 0) return false; - if (fastopenq->qlen >= fastopenq->max_qlen) { + if (fastopenq->qlen >= max_qlen) { struct request_sock *req1; spin_lock(&fastopenq->lock); req1 = fastopenq->rskq_rst_head; -- 2.39.2