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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 6F0DFC4360F for ; Mon, 18 Mar 2019 09:42:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3DDBC2075C for ; Mon, 18 Mar 2019 09:42:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552902172; bh=mKv0Ln/Gf8PYcJ4pAjYOpbfjB8FIfDDdfTpDtzrtFsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WNlSV3dYkn6jcbanQ7JbitlMr/nwfOfggVGWxByZejrgRY4UZh3NMTrFPhDvUH1sY dxlrF6ZfJfXKFWWCQZ+kNiFJPpDcmxlbmzJZn29bbxAJqIsBxV3OdkL4tQ8oGUVP2/ g7D+YBJxBA9kJuqTDz8RpVM6G9v7TFyrZWJuXbow= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727416AbfCRJcd (ORCPT ); Mon, 18 Mar 2019 05:32:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:40556 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727364AbfCRJcc (ORCPT ); Mon, 18 Mar 2019 05:32:32 -0400 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2EACD2083D; Mon, 18 Mar 2019 09:32:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552901551; bh=mKv0Ln/Gf8PYcJ4pAjYOpbfjB8FIfDDdfTpDtzrtFsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e0iDDpugtJFU2Ogg1plliGB+pVK2z3ZfDJv8K2xdv39vIt+utwGyJKmGKSZomLsbi 4CEfWaMpNep6CC+z5pw/qhI06bKeO56UNtqU0tAi2Ci99OQDD4yzsCKQqHyRQZfbI9 nGd3xI2bwVK79QZqX3U7jh2C8QhWZh9yHNNxx4pM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Abeni , David Ahern , "David S. Miller" Subject: [PATCH 4.19 28/52] ipv6: route: purge exception on removal Date: Mon, 18 Mar 2019 10:25:25 +0100 Message-Id: <20190318084016.851409348@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190318084013.532280682@linuxfoundation.org> References: <20190318084013.532280682@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni [ Upstream commit f5b51fe804ec2a6edce0f8f6b11ea57283f5857b ] When a netdevice is unregistered, we flush the relevant exception via rt6_sync_down_dev() -> fib6_ifdown() -> fib6_del() -> fib6_del_route(). Finally, we end-up calling rt6_remove_exception(), where we release the relevant dst, while we keep the references to the related fib6_info and dev. Such references should be released later when the dst will be destroyed. There are a number of caches that can keep the exception around for an unlimited amount of time - namely dst_cache, possibly even socket cache. As a result device registration may hang, as demonstrated by this script: ip netns add cl ip netns add rt ip netns add srv ip netns exec rt sysctl -w net.ipv6.conf.all.forwarding=1 ip link add name cl_veth type veth peer name cl_rt_veth ip link set dev cl_veth netns cl ip -n cl link set dev cl_veth up ip -n cl addr add dev cl_veth 2001::2/64 ip -n cl route add default via 2001::1 ip -n cl link add tunv6 type ip6tnl mode ip6ip6 local 2001::2 remote 2002::1 hoplimit 64 dev cl_veth ip -n cl link set tunv6 up ip -n cl addr add 2013::2/64 dev tunv6 ip link set dev cl_rt_veth netns rt ip -n rt link set dev cl_rt_veth up ip -n rt addr add dev cl_rt_veth 2001::1/64 ip link add name rt_srv_veth type veth peer name srv_veth ip link set dev srv_veth netns srv ip -n srv link set dev srv_veth up ip -n srv addr add dev srv_veth 2002::1/64 ip -n srv route add default via 2002::2 ip -n srv link add tunv6 type ip6tnl mode ip6ip6 local 2002::1 remote 2001::2 hoplimit 64 dev srv_veth ip -n srv link set tunv6 up ip -n srv addr add 2013::1/64 dev tunv6 ip link set dev rt_srv_veth netns rt ip -n rt link set dev rt_srv_veth up ip -n rt addr add dev rt_srv_veth 2002::2/64 ip netns exec srv netserver & sleep 0.1 ip netns exec cl ping6 -c 4 2013::1 ip netns exec cl netperf -H 2013::1 -t TCP_STREAM -l 3 & sleep 1 ip -n rt link set dev rt_srv_veth mtu 1400 wait %2 ip -n cl link del cl_veth This commit addresses the issue purging all the references held by the exception at time, as we currently do for e.g. ipv6 pcpu dst entries. v1 -> v2: - re-order the code to avoid accessing dst and net after dst_dev_put() Fixes: 93531c674315 ("net/ipv6: separate handling of FIB entries from dst based routes") Signed-off-by: Paolo Abeni Reviewed-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/route.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1282,18 +1282,29 @@ static DEFINE_SPINLOCK(rt6_exception_loc static void rt6_remove_exception(struct rt6_exception_bucket *bucket, struct rt6_exception *rt6_ex) { + struct fib6_info *from; struct net *net; if (!bucket || !rt6_ex) return; net = dev_net(rt6_ex->rt6i->dst.dev); + net->ipv6.rt6_stats->fib_rt_cache--; + + /* purge completely the exception to allow releasing the held resources: + * some [sk] cache may keep the dst around for unlimited time + */ + from = rcu_dereference_protected(rt6_ex->rt6i->from, + lockdep_is_held(&rt6_exception_lock)); + rcu_assign_pointer(rt6_ex->rt6i->from, NULL); + fib6_info_release(from); + dst_dev_put(&rt6_ex->rt6i->dst); + hlist_del_rcu(&rt6_ex->hlist); dst_release(&rt6_ex->rt6i->dst); kfree_rcu(rt6_ex, rcu); WARN_ON_ONCE(!bucket->depth); bucket->depth--; - net->ipv6.rt6_stats->fib_rt_cache--; } /* Remove oldest rt6_ex in bucket and free the memory