I found a bug which was manifest when linux boots and lots of ethernet
packets are coming in. I think the problem is because the fcc_enet.c
adds the network device in very early during the boot, and the driver is
happily calling netif_rx() on the received packets even though the interface
isn't officially "up". Linux appears not to like this, and would crash
sporadically, or predictibly if I have a program on another computer running
just blasting packets at the first one.
The fix is to just put an if around this section in fcc_enet_rx:
skb = dev_alloc_skb(pkt_len-4);
if (skb == NULL) {
printk("%s: Memory squeeze, dropping packet.\n",
dev->name);
cep->stats.rx_dropped++;
}
else {
skb->dev = dev;
skb_put(skb,pkt_len-4); /* Make room */
eth_copy_and_sum(skb,
(unsigned char *)__va(bdp->cbd_bufaddr),
pkt_len-4, 0);
skb->protocol=eth_type_trans(skb,dev);
netif_rx(skb);
}
So it becomes:
if(dev->flags & IFF_UP) { /* only do if iface is up */
skb = dev_alloc_skb(pkt_len-4);
if (skb == NULL) {
printk("%s: Memory squeeze, dropping
packet.\n", dev->name);
cep->stats.rx_dropped++;
}
else {
skb->dev = dev;
skb_put(skb,pkt_len-4); /* Make room */
eth_copy_and_sum(skb,
(unsigned char *)__va(bdp->cbd_bufaddr),
pkt_len-4, 0);
skb->protocol=eth_type_trans(skb,dev);
netif_rx(skb);
}
}
This fixes the crash bug.
-Dave
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