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 7A2D8C0015E for ; Tue, 25 Jul 2023 11:11:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234199AbjGYLL3 (ORCPT ); Tue, 25 Jul 2023 07:11:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234127AbjGYLLO (ORCPT ); Tue, 25 Jul 2023 07:11:14 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEB8C10F1 for ; Tue, 25 Jul 2023 04:10:26 -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 40F6F6166F for ; Tue, 25 Jul 2023 11:10:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D082C433C8; Tue, 25 Jul 2023 11:10:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1690283425; bh=cBpYCpLaI+9OgvbFaVO0Daks6ibu6Xk2STIlbexfbko=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qTX/cpwbNJ1UOp7iY44Pq+osc3mn6F9+9ey1nXNuYF9JEQNntoF3Aufcnj/ta+T/1 OALwLiZ2pRszmU8TxcBfjrl5KRzl4m/Opp1SxFqqn23ZvtjX08caXPogdDPGUwTI2l yJIcy0+No86gLUJZIW6tWFeo+FUq51bzrrTXG9C0= 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 72/78] tcp: annotate data-races around tp->notsent_lowat Date: Tue, 25 Jul 2023 12:47:03 +0200 Message-ID: <20230725104454.065898956@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 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 fe58b089f0b16..d8920f84f0a8d 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2012,7 +2012,11 @@ 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); } bool tcp_stream_memory_free(const struct sock *sk, int wake); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 29661f7e372d9..95e3e32d211a7 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3669,7 +3669,7 @@ 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: @@ -4161,7 +4161,7 @@ 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