From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net-next] net: packet: allow bind to device which is
 !IFF_UP
Date: Wed, 20 Dec 2017 15:06:56 -0500 (EST)
Message-ID: <20171220.150656.1052155984496301218.davem@davemloft.net>
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Cc: netdev@vger.kernel.org, Linyu.Yuan@alcatel-sbell.com.cn
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From: yuan linyu <cugyly@163.com>
Date: Wed, 20 Dec 2017 21:20:49 +0800

> From: yuan linyu <Linyu.Yuan@alcatel-sbell.com.cn>
> 
> this try to allow tcpdump to capture packet once device IFF_UP
> 
> Signed-off-by: yuan linyu <Linyu.Yuan@alcatel-sbell.com.cn>

I don't think this is such a great idea.

Even if it "works":

1) The behavior goes back decades, this means real applications can
   be broken by this change.

2) The feedback is useful, if I ran tcpdump on the wrong interface
   I'd like to get this error if the interface I mistakenly chose
   was done in order to help me figure this out.