From nobody Fri Dec 19 07:47:25 2025 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 92C54C00144 for ; Mon, 1 Aug 2022 12:03:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233089AbiHAMDH (ORCPT ); Mon, 1 Aug 2022 08:03:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233488AbiHAMBQ (ORCPT ); Mon, 1 Aug 2022 08:01:16 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB77C50195; Mon, 1 Aug 2022 04:53:31 -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 ams.source.kernel.org (Postfix) with ESMTPS id E7473B810A2; Mon, 1 Aug 2022 11:53:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AD69C433C1; Mon, 1 Aug 2022 11:53:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1659354808; bh=PNDp4lj8GLBQnWGKbaISuitpxGhHWJa1dxC+45jqmwQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PYaQEdwnau63TywpN/QCYQmEitWG0FNeeUBr2juj4Nw0MCBekzg4e+RojkSc089kl kvRWQl+vPjiGZNvNveARrv0jCGGPWO9DwiYWGhEH9lxNXNwwpq2PxnUhve5Nk1mSZc 8Gl2uKXm2osuJ/T60xCPuCkZCb1JY7kD03rhSaUE= 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 5.15 27/69] tcp: Fix a data-race around sysctl_tcp_challenge_ack_limit. Date: Mon, 1 Aug 2022 13:46:51 +0200 Message-Id: <20220801114135.620669092@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220801114134.468284027@linuxfoundation.org> References: <20220801114134.468284027@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Kuniyuki Iwashima commit db3815a2fa691da145cfbe834584f31ad75df9ff upstream. While reading sysctl_tcp_challenge_ack_limit, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 282f23c6ee34 ("tcp: implement RFC 5961 3.2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3622,7 +3622,7 @@ static void tcp_send_challenge_ack(struc /* Then check host-wide RFC 5961 rate limit. */ now =3D jiffies / HZ; if (now !=3D challenge_timestamp) { - u32 ack_limit =3D net->ipv4.sysctl_tcp_challenge_ack_limit; + u32 ack_limit =3D READ_ONCE(net->ipv4.sysctl_tcp_challenge_ack_limit); u32 half =3D (ack_limit + 1) >> 1; =20 challenge_timestamp =3D now;