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 BB235C04A68 for ; Wed, 27 Jul 2022 16:22:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235091AbiG0QW0 (ORCPT ); Wed, 27 Jul 2022 12:22:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234649AbiG0QWC (ORCPT ); Wed, 27 Jul 2022 12:22:02 -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 A5BC42E9EC; Wed, 27 Jul 2022 09:22:01 -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 42C59619A0; Wed, 27 Jul 2022 16:22:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53D1FC433C1; Wed, 27 Jul 2022 16:22:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658938920; bh=O4WxUKLOIbP4YbcycCwkwyd+Sq3DHdQ4vvJJCer2fag=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=awAaHZiNtbCDK1XCCUE+mpO77vPlO6z+DGDHzb963Osu9cmeoTNJVxbb3ZOz0cIEJ Ynva2AXuN42rasgFuiOdaDKrLsHEOYr1qkXzt0CvIbjXsf6gZP0zJplR5famZb4Svh oEiHQcLJH8YuxEQLdZ9tpwftGt4xG/LjIrFp2q4A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 15/26] tcp: Fix a data-race around sysctl_tcp_notsent_lowat. Date: Wed, 27 Jul 2022 18:10:44 +0200 Message-Id: <20220727160959.728471399@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727160959.122591422@linuxfoundation.org> References: <20220727160959.122591422@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 [ Upstream commit 55be873695ed8912eb77ff46d1d1cadf028bd0f3 ] While reading sysctl_tcp_notsent_lowat, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/tcp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 97df2f6fcbd7..164dc4f04d0f 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1788,7 +1788,7 @@ 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 ?: net->ipv4.sysctl_tcp_notsent_lowat; + return tp->notsent_lowat ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat); } static inline bool tcp_stream_memory_free(const struct sock *sk) -- 2.35.1