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 8C210C04A68 for ; Wed, 27 Jul 2022 16:41:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239427AbiG0Qlt (ORCPT ); Wed, 27 Jul 2022 12:41:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239570AbiG0QlA (ORCPT ); Wed, 27 Jul 2022 12:41:00 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 382AC5140C; Wed, 27 Jul 2022 09:29:32 -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 D2443B821BD; Wed, 27 Jul 2022 16:29:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F6E9C433C1; Wed, 27 Jul 2022 16:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658939369; bh=Lk+Blne/blYZaB0qzZO5oWNuvyqkY7TzTtvAIAIPXgs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AlIjts3Fk/Umj1Pk5ZBZhWE8P5OKnZbxcYTe+FAP+VtjaNjzbiy+r9rureqVnoCzh UAMa1RKkAjXry66KK0vqn5qDCFeeOozsmjVsNbXcvbG3RYaKGsPHyp3JO4UMIn3gTm 3x2qKu+iUHuLTQ0S5c554lQEtIx2N7PL3UvelcZU= 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 44/87] ipv4: Fix a data-race around sysctl_fib_multipath_use_neigh. Date: Wed, 27 Jul 2022 18:10:37 +0200 Message-Id: <20220727161010.838337691@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220727161008.993711844@linuxfoundation.org> References: <20220727161008.993711844@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 87507bcb4f5de16bb419e9509d874f4db6c0ad0f ] While reading sysctl_fib_multipath_use_neigh, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: a6db4494d218 ("net: ipv4: Consider failed nexthops in multipath routes") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/fib_semantics.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index 16fe03461563..28da0443f3e9 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -2209,7 +2209,7 @@ void fib_select_multipath(struct fib_result *res, int hash) } change_nexthops(fi) { - if (net->ipv4.sysctl_fib_multipath_use_neigh) { + if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) { if (!fib_good_nh(nexthop_nh)) continue; if (!first) { -- 2.35.1