[PATCH 2/3] Fix use of skb after netif_rx

From: Julia Lawall
Date: Sun Dec 09 2007 - 15:04:17 EST


From: Julia Lawall <julia@xxxxxxx>

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@xxxxxxx>
---

diff a/arch/xtensa/platform-iss/network.c b/arch/xtensa/platform-iss/network.c
--- a/arch/xtensa/platform-iss/network.c 2007-10-22 16:31:51.000000000 +0200
+++ b/arch/xtensa/platform-iss/network.c 2007-12-05 19:01:34.000000000 +0100
@@ -393,11 +393,11 @@ static int iss_net_rx(struct net_device
if (pkt_len > 0) {
skb_trim(skb, pkt_len);
skb->protocol = lp->tp.protocol(skb);
- // netif_rx(skb);
- netif_rx_ni(skb);

lp->stats.rx_bytes += skb->len;
lp->stats.rx_packets++;
+ // netif_rx(skb);
+ netif_rx_ni(skb);
return pkt_len;
}
kfree_skb(skb);
--
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