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From: David Miller <davem@davemloft.net>
Subject: Re: 2.6.38-rc1: arp triggers RTNL assertion
Date: Fri, 21 Jan 2011 13:06:57 -0800 (PST)
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 21 Jan 2011 19:52:56 +0100

> Here is how I fixed this, thanks again Jamie !
> 
> [PATCH] net: neighbour: pneigh_lookup() doesnt need RTNL

Eric, I don't think we can do this.

Fundamentally, any time a user operation changes the configuration
of the networking, we must hold the RTNL.

Eliding the RTNL for lookups is fine, but for things that change
state it is not.

I therefore think you'll need to rework the arp_ioctl() portions
of the commit that introduced this regression.