[UM]: Fix use of skb after netif_rx

Recently, Wang Chen submitted a patch
(d30f53aeb31d453a5230f526bea592af07944564) to move a call to netif_rx(skb)
after a subsequent reference to skb, because netif_rx may call kfree_skb on
its argument.  The same problem occurs in some other drivers as well.

This was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression skb, e,e1;
@@

(
 netif_rx(skb);
|
 netif_rx_ni(skb);
)
  ... when != skb = e
(
  skb = e1
|
* skb
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index 73681f1..3c6c44c 100644 (file)
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -98,10 +98,10 @@ static int uml_net_rx(struct net_device *dev)
        if (pkt_len > 0) {
                skb_trim(skb, pkt_len);
                skb->protocol = (*lp->protocol)(skb);
-               netif_rx(skb);
 
                lp->stats.rx_bytes += skb->len;
                lp->stats.rx_packets++;
+               netif_rx(skb);
                return pkt_len;
        }