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From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH 0/3] macvlan: support for guest vm direct rx/tx
Date: Fri, 27 Nov 2009 16:19:57 -0800 (PST)
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From: Arnd Bergmann <arnd@arndb.de>
Date: Sat, 28 Nov 2009 00:43:58 +0100

> On Friday 13 November 2009, Stephen Hemminger wrote:
>> Also, macvlan should really being calling netif_receive_skb()
>> not going through another queue/softirq cycle.
> 
> I've added a patch for this in my experimental queue now.
> When I last tried this, I saw a kernel stack overflow
> but it seems fine now.

I think it is unwise for any virtual device layer to use netif_receive_skb().
Just like tunnels they should always use netif_rx().

Otherwise stack overflow is a very real concern.