From patchwork Mon Jul 18 17:26:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuniyuki Iwashima X-Patchwork-Id: 12921502 X-Patchwork-Delegate: kuba@kernel.org 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 C2FB9C43334 for ; Mon, 18 Jul 2022 17:27:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235396AbiGRR1o (ORCPT ); Mon, 18 Jul 2022 13:27:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235624AbiGRR1f (ORCPT ); Mon, 18 Jul 2022 13:27:35 -0400 Received: from smtp-fw-9102.amazon.com (smtp-fw-9102.amazon.com [207.171.184.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C7882C13B for ; Mon, 18 Jul 2022 10:27:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1658165254; x=1689701254; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=aA7C+5l1MIsX/ZbytG/GBaYuDN1HD1puGeCSs425BEM=; b=u8Q3n4/Kv/+NtCuZfbNedfa482tLPUyelWzWd9PebisX0nNMe4j2Ewm3 PXsrCXgtiozPLsydlzrKmPFk/AGFOoDcFWwNvlb5NdJAYnBU9T1ZabxNf xx4xY83VzamdpUi57uYGU15ijBqx4vLZDvqSRPWWT9HOn6Um42bEkDSYg Y=; X-IronPort-AV: E=Sophos;i="5.92,281,1650931200"; d="scan'208";a="239553877" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-pdx-2b-2520d768.us-west-2.amazon.com) ([10.25.36.210]) by smtp-border-fw-9102.sea19.amazon.com with ESMTP; 18 Jul 2022 17:27:19 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2b-2520d768.us-west-2.amazon.com (Postfix) with ESMTPS id 00AA54443F; Mon, 18 Jul 2022 17:27:17 +0000 (UTC) Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.36; Mon, 18 Jul 2022 17:27:17 +0000 Received: from 88665a182662.ant.amazon.com (10.43.160.159) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.9; Mon, 18 Jul 2022 17:27:14 +0000 From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , David Ahern CC: Kuniyuki Iwashima , Kuniyuki Iwashima , Subject: [PATCH v1 net 01/15] ipv4: Fix a data-race around sysctl_fib_multipath_use_neigh. Date: Mon, 18 Jul 2022 10:26:39 -0700 Message-ID: <20220718172653.22111-2-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220718172653.22111-1-kuniyu@amazon.com> References: <20220718172653.22111-1-kuniyu@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.160.159] X-ClientProxiedBy: EX13D04UWA004.ant.amazon.com (10.43.160.234) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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 --- 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 d9fdcbae16ee..db7b2503f068 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -2216,7 +2216,7 @@ 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) {