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

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Date:   Thu, 4 May 2017 13:41:15 -0600
From:   David Ahern <dsahern@...il.com>
To:     Cong Wang <xiyou.wangcong@...il.com>, netdev@...r.kernel.org
Cc:     andreyknvl@...gle.com
Subject: Re: [Patch net v2] ipv6: reorder ip6_route_dev_notifier after
 ipv6_dev_notf

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.

Acked-by: David Ahern <dsahern@...il.com>
Tested-by: David Ahern <dsahern@...il.com>