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 F30F8C25B0C for ; Tue, 9 Aug 2022 18:03:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344460AbiHISDM (ORCPT ); Tue, 9 Aug 2022 14:03:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343849AbiHISCi (ORCPT ); Tue, 9 Aug 2022 14:02:38 -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 9C9F42611E; Tue, 9 Aug 2022 11:01:28 -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 5DB986102F; Tue, 9 Aug 2022 18:01:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C969BC433C1; Tue, 9 Aug 2022 18:01:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660068088; bh=yf73s1TIN7k8z2scu/2o/hJJ1mGHcwXT5PU9UwGww/Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OGXjXWCGdwsWq4DlmytcsJgXYw2pk8CSYBNnrIRbhWeoYDR1s04velHW5SqiyKL/d m6fopfCmMbfc1p7bDYD/teqkw5qL/j1aESN4Mv/Vqaqy7PuphvSRmTCkXEC30Fv43u cnRTVp8/RVyPxU1U5O7EQ7R1Ai3xA0apNQp8nEa4= 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 4.19 10/32] tcp: Fix a data-race around sysctl_tcp_challenge_ack_limit. Date: Tue, 9 Aug 2022 20:00:01 +0200 Message-Id: <20220809175513.421710176@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220809175513.082573955@linuxfoundation.org> References: <20220809175513.082573955@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 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 @@ -3468,7 +3468,7 @@ static void tcp_send_challenge_ack(struc /* Then check host-wide RFC 5961 rate limit. */ now = jiffies / HZ; if (now != challenge_timestamp) { - u32 ack_limit = net->ipv4.sysctl_tcp_challenge_ack_limit; + u32 ack_limit = READ_ONCE(net->ipv4.sysctl_tcp_challenge_ack_limit); u32 half = (ack_limit + 1) >> 1; challenge_timestamp = now;