netdev - Re: [Patch net v2] ipv6: reorder ip6_route_dev_notifier after ipv6_dev

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Date:   Mon, 08 May 2017 11:37:47 -0400 (EDT)
From:   David Miller <davem@...emloft.net>
To:     dsahern@...il.com
Cc:     xiyou.wangcong@...il.com, netdev@...r.kernel.org,
        andreyknvl@...gle.com
Subject: Re: [Patch net v2] ipv6: reorder ip6_route_dev_notifier after
 ipv6_dev_notf

From: David Ahern <dsahern@...il.com>
Date: Thu, 4 May 2017 13:41:15 -0600

> On 5/4/17 11:36 AM, Cong Wang wrote:
>> For each netns (except init_net), we initialize its null entry
>> in 3 places:
>> 
>> 1) The template itself, as we use kmemdup()
>> 2) Code around dst_init_metrics() in ip6_route_net_init()
>> 3) ip6_route_dev_notify(), which is supposed to initialize it after
>>    loopback registers
>> 
>> Unfortunately the last one still happens in a wrong order because
>> we expect to initialize net->ipv6.ip6_null_entry->rt6i_idev to
>> net->loopback_dev's idev, so we have to do that after we add
>> idev to it. However, this notifier has priority == 0 same as
>> ipv6_dev_notf, and ipv6_dev_notf is registered after
>> ip6_route_dev_notifier so it is called actually after
>> ip6_route_dev_notifier.
>> 
>> Fix it by picking a smaller priority for ip6_route_dev_notifier.
>> Also, we have to release the refcnt accordingly when unregistering
>> loopback_dev because device exit functions are called before subsys
>> exit functions.
>> 
>> Cc: David Ahern <dsahern@...il.com>
>> Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
>> ---
> 
> Commit message needs a tie in to the problem that Andrey reported. It
> solves the same problem for namespaces other than init_net.

Cong, please update the commit message as David is requesting.

Thanks.