netdev - Re: sock_create_kern() and (lack of) get

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Date:   Wed, 3 May 2017 09:33:10 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     David Laight <David.Laight@...lab.com>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: sock_create_kern() and (lack of) get_net()

On Wed, May 3, 2017 at 4:39 AM, David Laight <David.Laight@...lab.com> wrote:
> I suspect that many of the sockets created with 'kern=1' are not 'special'
> and should hold a reference to the namespace.

They are special if they are created in net init, which means they
have the same life-time with netns. They should NOT hold a refcnt,
otherwise who would release the last netns refcnt? net exit is called
when refcnt reaches 0, if you really held it, it is always at least 1.