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 DF855C04A94 for ; Wed, 9 Aug 2023 11:21:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233541AbjHILVD (ORCPT ); Wed, 9 Aug 2023 07:21:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233542AbjHILVC (ORCPT ); Wed, 9 Aug 2023 07:21:02 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEE05FA for ; Wed, 9 Aug 2023 04:21:01 -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 8E9BE631E1 for ; Wed, 9 Aug 2023 11:21:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D9D6C433C8; Wed, 9 Aug 2023 11:21:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691580061; bh=Dm6bfopdTDWnSNXRKctymaICBEIE+G88r3ySXY5m6e4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0+5gshDc1+Q/rx7jjTLiqoZ1h6RtShlGtTxwuEfA2dJ2BuIsX7pYqSigt5cWtIUoU HyAU4Tg45W6adnGbXeA8NowrvX/TcDLxPz08O9qtAqt+APUIaZuCWZSiwCAhOQfdI4 PdREfrJITpSEUGNuVShoj9Zuxt4HidYW6fYaK5Mk= 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 4.19 214/323] tcp: annotate data-races around tp->notsent_lowat Date: Wed, 9 Aug 2023 12:40:52 +0200 Message-ID: <20230809103707.907837336@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103658.104386911@linuxfoundation.org> References: <20230809103658.104386911@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 1aeb87bc1440c5447a7fa2d6e3c2cca52cbd206b ] tp->notsent_lowat can be read locklessly from do_tcp_getsockopt() and tcp_poll(). Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option") Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/r/20230719212857.3943972-10-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/tcp.h | 6 +++++- net/ipv4/tcp.c | 4 ++-- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 22cca858f2678..c6c48409e7b42 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1883,7 +1883,11 @@ void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp) { struct net *net = sock_net((struct sock *)tp); - return tp->notsent_lowat ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); + u32 val; + + val = READ_ONCE(tp->notsent_lowat); + + return val ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); } /* @wake is one when sk_stream_write_space() calls us. diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 853a33bf8863e..373bf3d3be592 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3099,7 +3099,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level, err = tcp_repair_set_window(tp, optval, optlen); break; case TCP_NOTSENT_LOWAT: - tp->notsent_lowat = val; + WRITE_ONCE(tp->notsent_lowat, val); sk->sk_write_space(sk); break; case TCP_INQ: @@ -3569,7 +3569,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level, val = tcp_time_stamp_raw() + tp->tsoffset; break; case TCP_NOTSENT_LOWAT: - val = tp->notsent_lowat; + val = READ_ONCE(tp->notsent_lowat); break; case TCP_INQ: val = tp->recvmsg_inq; -- 2.39.2