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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30B2DC169C4 for ; Wed, 6 Feb 2019 19:04:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 046AE2075C for ; Wed, 6 Feb 2019 19:04:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726270AbfBFTEX (ORCPT ); Wed, 6 Feb 2019 14:04:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38998 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725959AbfBFTEX (ORCPT ); Wed, 6 Feb 2019 14:04:23 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 61D6A8AE72; Wed, 6 Feb 2019 19:04:23 +0000 (UTC) Received: from localhost (ovpn-200-19.brq.redhat.com [10.40.200.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B5A345D9D6; Wed, 6 Feb 2019 19:04:21 +0000 (UTC) Date: Wed, 6 Feb 2019 20:04:17 +0100 From: Stefano Brivio To: David Ahern Cc: Hangbin Liu , netdev@vger.kernel.org, David Miller Subject: Re: [PATCH net 1/2] geneve: should not call rt6_lookup() when ipv6 was disabled Message-ID: <20190206200417.2c1b1e78@redhat.com> In-Reply-To: <9b7585c2-bab6-1c6c-7bab-9542406acf1a@gmail.com> References: <20190206125111.5286-1-liuhangbin@gmail.com> <20190206125111.5286-2-liuhangbin@gmail.com> <9b7585c2-bab6-1c6c-7bab-9542406acf1a@gmail.com> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 06 Feb 2019 19:04:23 +0000 (UTC) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 6 Feb 2019 10:54:01 -0800 David Ahern wrote: > On 2/6/19 4:51 AM, Hangbin Liu wrote: > > When we add a new GENEVE device with IPv6 remote, checking only for > > IS_ENABLED(CONFIG_IPV6) is not enough as we may disable IPv6 in kernel > > cmd(ipv6.disable=1), which will cause a NULL pointer dereference. > > > > Reported-by: Jianlin Shi > > Signed-off-by: Hangbin Liu > > --- > > drivers/net/geneve.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c > > index 58bbba8582b0..0658715581e3 100644 > > --- a/drivers/net/geneve.c > > +++ b/drivers/net/geneve.c > > @@ -1512,6 +1512,10 @@ static void geneve_link_config(struct net_device *dev, > > } > > #if IS_ENABLED(CONFIG_IPV6) > > case AF_INET6: { > > + struct inet6_dev *idev = in6_dev_get(dev); > > + if (!idev) > > + break; > > Since you don't need an idev reference rcu_access_pointer should be > enough to say v6 is enabled on this device. ie., add a helper to check > that rcu_access_pointer(dev->ip6_ptr) is non-NULL I guess if (__in6_dev_get(dev)) is already good, no? This is called under RTNL. -- Stefano