From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <xiyou.wangcong@gmail.com>
Subject: Re: [PATCH 0/2] bring UP loopback device at initialziation
Date: Wed, 5 Jul 2017 10:48:56 -0700
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References: <20170704191615.6412-1-mahesh@bandewar.net> <20170705.092032.1482668095877350196.davem@davemloft.net>
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Cc: David Miller <davem@davemloft.net>,
        Mahesh Bandewar <mahesh@bandewar.net>,
        James Morris <jmorris@namei.org>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Patrick McHardy <kaber@trash.net>,
        Eric Dumazet <edumazet@google.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        linux-netdev <netdev@vger.kernel.org>
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On Wed, Jul 5, 2017 at 8:59 AM, Mahesh Bandewar (=E0=A4=AE=E0=A4=B9=E0=A5=
=87=E0=A4=B6 =E0=A4=AC=E0=A4=82=E0=A4=A1=E0=A5=87=E0=A4=B5=E0=A4=BE=E0=A4=
=B0)
<maheshb@google.com> wrote:
> Systems have only one lo device (since ages) and that is usually taken
> care at the boot time. Now with the namespaces it's not just one
> device as it's per namespace and though not much this patch will
> benefit a little. Probably we should ask a question - is it going to
> have any bad effects? I couldn't find any and my RFC patch did not get
> me any such feedback. As far as the good effects are concerned, it has
> already found a bug (another patch in this series)! Also sometime back
> I did experience weird behavior inside net-namespace if you forget to
> bring-up the loopback device. I didn't pay too much attention as
> bringing up the lo device fixed it.
>

I wonder if it is too late to change this since this behavior is probably
from the beginning of network namespace. A networkless netns is also
useful at least for testing purpose, we do use it as a sandbox.