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 E4768C00144 for ; Mon, 1 Aug 2022 11:51:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231571AbiHALvZ (ORCPT ); Mon, 1 Aug 2022 07:51:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231840AbiHALuQ (ORCPT ); Mon, 1 Aug 2022 07:50:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 00CCF3D59D; Mon, 1 Aug 2022 04:49:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5EB26612AB; Mon, 1 Aug 2022 11:49:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B318C433C1; Mon, 1 Aug 2022 11:49:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1659354547; bh=mn4KD0k0fVIvnt863IwUl1nXyDS8ebDv3M3Jhof39Ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=07ygNVKQLTh9Z9kjRezo2FRXMBm6QiESxfg/JLK5nSaMNM/yHvQjySxl8ZNtjYJ/n OZP4xund8sJL+sG1La570qKIXzf3NDWLO/nmdV83QPDbgakKZX/+Pu1XKP7PvyIPcY zIEU/pyRSw6UiMP7xrXDTOgF51t2m9UdP4vhVysA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , "David S. Miller" Subject: [PATCH 5.4 04/34] tcp: Fix data-races around sysctl_tcp_dsack. Date: Mon, 1 Aug 2022 13:46:44 +0200 Message-Id: <20220801114128.225736271@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220801114128.025615151@linuxfoundation.org> References: <20220801114128.025615151@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kuniyuki Iwashima commit 58ebb1c8b35a8ef38cd6927431e0fa7b173a632d upstream. While reading sysctl_tcp_dsack, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_input.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4260,7 +4260,7 @@ static void tcp_dsack_set(struct sock *s { struct tcp_sock *tp = tcp_sk(sk); - if (tcp_is_sack(tp) && sock_net(sk)->ipv4.sysctl_tcp_dsack) { + if (tcp_is_sack(tp) && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_dsack)) { int mib_idx; if (before(seq, tp->rcv_nxt)) @@ -4306,7 +4306,7 @@ static void tcp_send_dupack(struct sock NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOST); tcp_enter_quickack_mode(sk, TCP_MAX_QUICKACKS); - if (tcp_is_sack(tp) && sock_net(sk)->ipv4.sysctl_tcp_dsack) { + if (tcp_is_sack(tp) && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_dsack)) { u32 end_seq = TCP_SKB_CB(skb)->end_seq; tcp_rcv_spurious_retrans(sk, skb);