Re: [34/49] igb: only use vlan_gro_receive if vlans are registered

[Alexander Duyck]

On 1/5/2011 3:00 PM, Greg KH wrote:
> 2.6.32-longterm review patch.  If anyone has any objections, please let us know.
>
> ------------------
>
> From: Alexander Duyck<alexander.h.duyck@xxxxxxxxx>
>
> commit 31b24b955c3ebbb6f3008a6374e61cf7c05a193c upstream.
>
> This change makes it so that vlan_gro_receive is only used if vlans have been
> registered to the adapter structure.  Previously we were just sending all vlan
> tagged frames in via this function but this results in a null pointer
> dereference when vlans are not registered.
>
> [ This fixes bugzilla entry 15582 -Eric Dumazet]
>
> Signed-off-by: Alexander Duyck<alexander.h.duyck@xxxxxxxxx>
> Signed-off-by: Jeff Kirsher<jeffrey.t.kirsher@xxxxxxxxx>
> Acked-by: Eric Dumazet<eric.dumazet@xxxxxxxxx>
> Signed-off-by: David S. Miller<davem@xxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman<gregkh@xxxxxxx>
>
> ---
>   drivers/net/igb/igb_main.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/drivers/net/igb/igb_main.c
> +++ b/drivers/net/igb/igb_main.c
> @@ -4560,7 +4560,7 @@ static void igb_receive_skb(struct igb_r
>   	bool vlan_extracted = (adapter->vlgrp&&  (status&  E1000_RXD_STAT_VP));
>
>   	skb_record_rx_queue(skb, ring->queue_index);
> -	if (vlan_extracted)
> +	if (vlan_extracted && adapter->vlgrp)
>   		vlan_gro_receive(&ring->napi, adapter->vlgrp,
>   		                 le16_to_cpu(rx_desc->wb.upper.vlan),
>   		                 skb);

I was just reviewing some history on this and I noticed that this patch 
appears to be applied to the wrong kernel.  The change isn't needed for 
2.6.32 as evidenced by the fact that vlan_extracted already includes 
adapter->vlgrp as part of computing it's value.  However, the change is 
needed for 2.6.33.  The original bugzilla include the patch for that kernel.

Thanks,

Alex

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