netdev - Re: [PATCHv2 net] ipvs: call ip_vs_dst_notifier earlier than ipv6_dev

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Date:   Fri, 16 Nov 2018 09:10:16 +0200 (EET)
From:   Julian Anastasov <ja@....bg>
To:     Xin Long <lucien.xin@...il.com>
cc:     network dev <netdev@...r.kernel.org>,
        netfilter-devel@...r.kernel.org,
        "David S. Miller" <davem@...emloft.net>, pablo@...filter.org,
        Hans Schillstrom <hans@...illstrom.com>,
        Simon Horman <horms@...ge.net.au>
Subject: Re: [PATCHv2 net] ipvs: call ip_vs_dst_notifier earlier than
 ipv6_dev_notf


	Hello,

On Thu, 15 Nov 2018, Xin Long wrote:

> ip_vs_dst_event is supposed to clean up all dst used in ipvs'
> destinations when a net dev is going down. But it works only
> when the dst's dev is the same as the dev from the event.
> 
> Now with the same priority but late registration,
> ip_vs_dst_notifier is always called later than ipv6_dev_notf
> where the dst's dev is set to lo for NETDEV_DOWN event.
> 
> As the dst's dev lo is not the same as the dev from the event
> in ip_vs_dst_event, ip_vs_dst_notifier doesn't actually work.
> Also as these dst have to wait for dest_trash_timer to clean
> them up. It would cause some non-permanent kernel warnings:
> 
>   unregister_netdevice: waiting for br0 to become free. Usage count = 3
> 
> To fix it, call ip_vs_dst_notifier earlier than ipv6_dev_notf
> by increasing its priority to ADDRCONF_NOTIFY_PRIORITY + 5.
> 
> Note that for ipv4 route fib_netdev_notifier doesn't set dst's
> dev to lo in NETDEV_DOWN event, so this fix is only needed when
> IP_VS_IPV6 is defined.
> 
> v1->v2:
>   - apply it only when CONFIG_IP_VS_IPV6 is defined.
> 
> Fixes: 7a4f0761fce3 ("IPVS: init and cleanup restructuring")
> Reported-by: Li Shuang <shuali@...hat.com>
> Signed-off-by: Xin Long <lucien.xin@...il.com>

Acked-by: Julian Anastasov <ja@....bg>

> ---
>  net/netfilter/ipvs/ip_vs_ctl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index 83395bf6..432141f 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -3980,6 +3980,9 @@ static void __net_exit ip_vs_control_net_cleanup_sysctl(struct netns_ipvs *ipvs)
>  
>  static struct notifier_block ip_vs_dst_notifier = {
>  	.notifier_call = ip_vs_dst_event,
> +#ifdef CONFIG_IP_VS_IPV6
> +	.priority = ADDRCONF_NOTIFY_PRIORITY + 5,
> +#endif
>  };
>  
>  int __net_init ip_vs_control_net_init(struct netns_ipvs *ipvs)
> -- 
> 2.1.0

Regards

--
Julian Anastasov <ja@....bg>