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 84AA8C00144 for ; Mon, 1 Aug 2022 11:49:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231737AbiHALtb (ORCPT ); Mon, 1 Aug 2022 07:49:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231646AbiHALs6 (ORCPT ); Mon, 1 Aug 2022 07:48:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6647F3D5A0; Mon, 1 Aug 2022 04:48:33 -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 78BE9612D0; Mon, 1 Aug 2022 11:48:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85DB3C433C1; Mon, 1 Aug 2022 11:48:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1659354511; bh=WsiqZ7jEzFRn1p8SOJ69NiOonWK97kvhuVRggOjJgac=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rKTC4sh3NCKYTHPTIYJanE9jmnximoRWu3M84eQujenQyXCaL+jsQ+xO2ct1sHNvz +RENIb107zobYR6trgSzhQFr5xsR0ps5YE4QoV6z5s1wVbJ01+MFQyVkz0BglYfDqK cJihNQt1lR4JCSgp0pPpdMHqFIF3zcckWVYE0fa0= 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 5.4 21/34] tcp: Fix a data-race around sysctl_tcp_invalid_ratelimit. Date: Mon, 1 Aug 2022 13:47:01 +0200 Message-Id: <20220801114128.842661951@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 [ Upstream commit 2afdbe7b8de84c28e219073a6661080e1b3ded48 ] While reading sysctl_tcp_invalid_ratelimit, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 032ee4236954 ("tcp: helpers to mitigate ACK loops by rate-limiting out-of-window dupacks") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_input.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index b760ad0b16d9..7af5e6acf41a 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3436,7 +3436,8 @@ static bool __tcp_oow_rate_limited(struct net *net, int mib_idx, if (*last_oow_ack_time) { s32 elapsed = (s32)(tcp_jiffies32 - *last_oow_ack_time); - if (0 <= elapsed && elapsed < net->ipv4.sysctl_tcp_invalid_ratelimit) { + if (0 <= elapsed && + elapsed < READ_ONCE(net->ipv4.sysctl_tcp_invalid_ratelimit)) { NET_INC_STATS(net, mib_idx); return true; /* rate-limited: don't send yet! */ } -- 2.35.1