mac80211: fix mesh forwarding

Under memory pressure, the mac80211 mesh code
may helpfully print a message that it failed
to clone a mesh frame and then will proceed
to crash trying to use it anyway. Fix that.

Cc: stable@kernel.org [2.6.27+]
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Acked-by: NJavier Cardona <javier@cozybit.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

net/mac80211/rx.c

@@ -1788,9 +1788,11 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
 
 			fwd_skb = skb_copy(skb, GFP_ATOMIC);
 
-			if (!fwd_skb && net_ratelimit())
+			if (!fwd_skb && net_ratelimit()) {
 				printk(KERN_DEBUG "%s: failed to clone mesh frame\n",
 						   sdata->name);
+				goto out;
+			}
 
 			fwd_hdr =  (struct ieee80211_hdr *) fwd_skb->data;
 			memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
@@ -1828,6 +1830,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
 		}
 	}
 
+ out:
 	if (is_multicast_ether_addr(hdr->addr1) ||
 	    sdata->dev->flags & IFF_PROMISC)
 		return RX_CONTINUE;