From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0C9F91ED38 for ; Tue, 25 Jul 2023 11:34:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84CA0C433C8; Tue, 25 Jul 2023 11:34:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690284871; bh=SV6sjQJIfQVbe3mxOIK0m93sE8l0mPL0kD6YJ9CiPg8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x8yxbRiyQcP8xsD648L51QOvPIzOeKmrhzfIph/KMkrrSHLzg8g4qzlvwbifT9bq8 9g2Q8Cm5wfM87OipgtJTbnGGLISdcaXIY+/3WHZREcd7NrcQQPrlwB/rG4blWlBaTN Bjcq3M/Vs/V6Sr5YctdWi4OU7Khi9gG9SRRoKAiU= 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 5.10 502/509] tcp: annotate data-races around tp->notsent_lowat Date: Tue, 25 Jul 2023 12:47:21 +0200 Message-ID: <20230725104616.724300113@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230725104553.588743331@linuxfoundation.org> References: <20230725104553.588743331@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 be81a930b91fa..dcca41f3a2240 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1991,7 +1991,11 @@ 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 50d674d35e520..8a441dfd258d5 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3437,7 +3437,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname, 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: @@ -3913,7 +3913,7 @@ 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