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 820ECC25B0D for ; Tue, 9 Aug 2022 18:03:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245703AbiHISDt (ORCPT ); Tue, 9 Aug 2022 14:03:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344457AbiHISDL (ORCPT ); Tue, 9 Aug 2022 14:03:11 -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 3373D26ADB; Tue, 9 Aug 2022 11:01:51 -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 151AD61012; Tue, 9 Aug 2022 18:01:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82052C433D7; Tue, 9 Aug 2022 18:01:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660068110; bh=nWkaHB4aObE4+ORXQz/gbELbp69I+2ype2nxZe9a19U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iOhBMOUbVNQ52uVzKGFoOVHEBuoGke5N8942aYr5Ifsey68O0HTid97VCiRfs5+/a wgKfgy1cCuwG/NOq1ltM6EdHW2i/fXyO63gksfeTawZGkNdR4auWKsxYUNKDVgIkI7 6qibuxIxFUuwo2nYkduWsJi5OO4ef2JnRlsVpHo4= 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 08/32] tcp: Fix a data-race around sysctl_tcp_nometrics_save. Date: Tue, 9 Aug 2022 19:59:59 +0200 Message-Id: <20220809175513.362227305@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: stable@vger.kernel.org From: Kuniyuki Iwashima commit 8499a2454d9e8a55ce616ede9f9580f36fd5b0f3 upstream. While reading sysctl_tcp_nometrics_save, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. 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_metrics.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -329,7 +329,7 @@ void tcp_update_metrics(struct sock *sk) int m; sk_dst_confirm(sk); - if (net->ipv4.sysctl_tcp_nometrics_save || !dst) + if (READ_ONCE(net->ipv4.sysctl_tcp_nometrics_save) || !dst) return; rcu_read_lock();