Message-ID: <1348145269.4161.28.camel@jlt4.sipsolutions.net> (sfid-20120920_144723_081920_00B84F43)
Subject: Re: regression: tethering fails in 3.5 with iwlwifi
From: Johannes Berg <johannes@sipsolutions.net>
To: Eric Dumazet <edumazet@google.com>
Cc: artem.bityutskiy@linux.intel.com, linux-wireless@vger.kernel.org,
	netdev <netdev@vger.kernel.org>
Date: Thu, 20 Sep 2012 14:47:49 +0200
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On Thu, 2012-09-20 at 14:45 +0200, Eric Dumazet wrote:
> I guess you only need to make sure 14 bytes of ethernet header are
> available before eth_type_trans(skb, dev);
> 
> diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
> index 61c621e..ffe5f84 100644
> --- a/net/mac80211/rx.c
> +++ b/net/mac80211/rx.c
> @@ -1795,9 +1795,13 @@ ieee80211_deliver_skb(struct ieee80211_rx_data *rx)
> 
>                 if (skb) {
>                         /* deliver to local stack */
> -                       skb->protocol = eth_type_trans(skb, dev);
> -                       memset(skb->cb, 0, sizeof(skb->cb));
> -                       netif_receive_skb(skb);
> +                       if (pskb_may_pull(skb, sizeof(struct ethhdr))) {
> +                               skb->protocol = eth_type_trans(skb, dev);
> +                               memset(skb->cb, 0, sizeof(skb->cb));
> +                               netif_receive_skb(skb);
> +                       } else {
> +                               kfree_skb(skb);
> +                       }
>                 }
>         }

Yeah I was looking at the same code just now. However, we had actually
inserted the skb_linearize() *after* eth_type_trans(), so I'm confused.
Maybe it still works, more or less by accident?

johannes