linux-kernel - Re: [PATCH] net: route: Fix vrf dst

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Date:   Sat, 4 May 2019 19:33:51 +0800
From:   linmiaohe <linmiaohe@...wei.com>
To:     <davem@...emloft.net>, <christian@...uner.io>,
        <roopa@...ulusnetworks.com>, <dsahern@...il.com>,
        <Jason@...c4.com>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
CC:     mousuanming <mousuanming@...wei.com>,
        Mingfangsen <mingfangsen@...wei.com>
Subject: Re: [PATCH] net: route: Fix vrf dst_entry ref count false increasing



On 2019/5/4 16:03, linmiaohe wrote:
> From: Suanming.Mou <mousuanming@...wei.com>
> 
> When config ip in default vrf same as the ip in specified
> vrf, fib_lookup will return the route from table local
> even if the in device is an enslaved l3mdev. Then the
> dst_entry will hold the vrf device rather than loopback
> device in local_input of function ip_route_input_slow.
> So vrf dst_entry is false increased by route from table
> local.
> 
> Here is reproduce step:
> 1.enslave enp4s0 to vrf2, and config ip address:
> ip link add vrf2 type vrf table 1
> ip link set vrf2 up
> ip link set enp4s0 master vrf2
> ip addr ad 125.1.1.1/16 dev enp4s0
> 
> 2.config same ip in default vrf:
> ip addr ad 125.1.1.1/16 dev enp6s0
> 
> 3.config peer and ping:
> ip vrf exec vrf2 ping 125.1.1.2 -c 3
> 
> 4.del vrf2 link:
> ip link del vrf2
> 
> And "unregister_netdevice: waiting for vrf2 to become free.
> Usage count = 1" will occur.
> 
> Signed-off-by: Suanming.Mou <mousuanming@...wei.com>
> Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
> ---
>  net/core/fib_rules.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
> index ffbb827723a2..1a2c11ed1585 100644
> --- a/net/core/fib_rules.c
> +++ b/net/core/fib_rules.c
> @@ -263,6 +263,11 @@ static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
>  	if (rule->tun_id && (rule->tun_id != fl->flowi_tun_key.tun_id))
>  		goto out;
> 
> +	if (!rule->l3mdev &&
> +	    (netif_index_is_l3_master(rule->fr_net, fl->flowi_iif) ||
> +	     netif_index_is_l3_master(rule->fr_net, fl->flowi_oif)))
> +		goto out;
> +
>  	if (rule->l3mdev && !l3mdev_fib_rule_match(rule->fr_net, fl, arg))
>  		goto out;
> 

I'am sorry, but I think this fix looks bad because this patch make vrf
working with other ip rule impossible. I will send anothor patch to fix
this. Thanks.