netdev - Re: [PATCH v2 net] net-gro: reset skb->pkt_type in napi_reuse

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Message-Id: <20181117.220045.440936435362041574.davem@davemloft.net>
Date:   Sat, 17 Nov 2018 22:00:45 -0800 (PST)
From:   David Miller <davem@...emloft.net>
To:     edumazet@...gle.com
Cc:     netdev@...r.kernel.org, eric.dumazet@...il.com
Subject: Re: [PATCH v2 net] net-gro: reset skb->pkt_type in napi_reuse_skb()

From: Eric Dumazet <edumazet@...gle.com>
Date: Sat, 17 Nov 2018 21:57:02 -0800

> eth_type_trans() assumes initial value for skb->pkt_type
> is PACKET_HOST.
> 
> This is indeed the value right after a fresh skb allocation.
> 
> However, it is possible that GRO merged a packet with a different
> value (like PACKET_OTHERHOST in case macvlan is used), so
> we need to make sure napi->skb will have pkt_type set back to
> PACKET_HOST.
> 
> Otherwise, valid packets might be dropped by the stack because
> their pkt_type is not PACKET_HOST.
> 
> napi_reuse_skb() was added in commit 96e93eab2033 ("gro: Add
> internal interfaces for VLAN"), but this bug always has
> been there.
> 
> Fixes: 96e93eab2033 ("gro: Add internal interfaces for VLAN")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

I was wondering about that WARN_ON in v1 :-)

Applied and queued up for -stable.