Re: Kernel panic eth2 mirred redirect to ifb0

[Eric Dumazet <eric.dumazet@gmail.com>]

Le lundi 20 décembre 2010 à 16:56 +0800, Changli Gao a écrit :
> 2010/12/20 Paweł Staszewski <pstaszewski@itcare.pl>:
> >>
> > Yes reverting this patch solves the problem.
> >
> >
> 
> I am not sure reverting is the right fix. Maybe you can try this patch
> attached instead.
> 
> BTW: there are some others NIC drivers and net_sched actions don't
> take care of shared skbs.
> 

This patch cant be right as is.

        if (skb_is_gso(skb)) {
+               if (skb_shared(skb)) {
+                       struct sk_buff *nskb;
+
+                       nskb = skb_clone(skb, GFP_ATOMIC);
+                       if (!nskb)
+                               return -ENOMEM;
+                       kfree_skb(skb); // HERE
+                       skb = nskb;
+               }

You free original skb, while caller might dereference it later.
So you must pass cloned skb back to caller.

(line 6393 :)
 count = ixgbe_tx_map(adapter, tx_ring, skb, tx_flags, first);