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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 A7608C43381 for ; Thu, 21 Feb 2019 15:10:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 730AA2083B for ; Thu, 21 Feb 2019 15:10:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ehqOo9li" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728126AbfBUPKi (ORCPT ); Thu, 21 Feb 2019 10:10:38 -0500 Received: from mail-pf1-f181.google.com ([209.85.210.181]:40951 "EHLO mail-pf1-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725858AbfBUPKh (ORCPT ); Thu, 21 Feb 2019 10:10:37 -0500 Received: by mail-pf1-f181.google.com with SMTP id h1so13959494pfo.7 for ; Thu, 21 Feb 2019 07:10:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Vt5QQNB/mF/KKLwoGLvVW7gJjnmmejii/KUZl2mPPy8=; b=ehqOo9li4P6+TI9EdB5LJiFjSjThcpEi2svHI8jaesiB5nXd7f9r4T3FkuuarK+mas LXvwZoJMTva9wZlM4IGFgxbkp4hD8NiMrr+aEq9Ajqgbn6gKDu+2sxMfyupM+UATHqZp mloFKwL15NohsuJ57SS9aR+2NzRDbXrkzjRlWi6qQTgPuLaTF0/dZPFrrYFaOPYAQ6XX tfamSle0yRer7KKF+XcyHtxBE2shrbjbJZXUIoxpvjsgX3kQjQMuxrwfKLeHIRjn/b3H cLQYL+6KkJpT1WDuo6k2E6QHHiSPrvDO3MlAnXB5XbMeg7hbw0hL5ndNhtp8hmNbXZ6p rrBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Vt5QQNB/mF/KKLwoGLvVW7gJjnmmejii/KUZl2mPPy8=; b=P7PeitMNecryG/JglVkvRWrDDXMb+qAc+zqMCg05Fohg4Rdas1avFC3ODs6ykjGpRc 1HxIT760JrVnJLkDvJzvwj/8DRHfJmr7kln7e5/dF5Yg5JhjyFmjSVijJrUUBt7/hLYQ DTjKqqZUHTHT1kDz1f8lCcnfAeh38+EBuFYRgR1+su6iLov1kmQURXbXLIjcdu3MVs7q b4rP91YnubV4pW1NCAOWGWeEmLInqXvCNrB06Adg6w2Lw5EhmWFGX1e8LWmbJrYKjznc jjQaroiRhllBB+dWShfLT3rEPDlGaqU1IFYw6DDdjtLJ2pcNFT8d3U5lKV3zMbpbGJL/ zl0A== X-Gm-Message-State: AHQUAuaJicjNiiuBsb3eexa1FxPzLgATreCyRRTwxUN+Z1kpuzyU6vxw yJg7HmxUgP8CbmaJXmlYUOA= X-Google-Smtp-Source: AHgI3Ib8pkW824a/irwnF8QOVQNc/1WHLrt+ewpvOrDkAitCWHnk9Nq+lndT2Vls0mo7yj0wZdDxIQ== X-Received: by 2002:a62:564d:: with SMTP id k74mr32173630pfb.19.1550761835220; Thu, 21 Feb 2019 07:10:35 -0800 (PST) Received: from [172.27.227.247] ([216.129.126.118]) by smtp.googlemail.com with ESMTPSA id f14sm24503659pgv.23.2019.02.21.07.10.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Feb 2019 07:10:34 -0800 (PST) Subject: Re: [PATCH net v2] ipv6: route: purge exception on removal To: Paolo Abeni , netdev@vger.kernel.org Cc: "David S. Miller" References: <1cf1aef01dd9294347df6e339d2f8f042172fb54.1550679150.git.pabeni@redhat.com> From: David Ahern Message-ID: Date: Thu, 21 Feb 2019 10:10:32 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1cf1aef01dd9294347df6e339d2f8f042172fb54.1550679150.git.pabeni@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2/20/19 12:18 PM, Paolo Abeni wrote: > 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 > --- > net/ipv6/route.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > I am surprised this was not found by the existing pmtu script which creates exceptions. Please add this test case to selftests to capture this specific set of events. Reviewed-by: David Ahern Thanks for the resolving.