drivers: net: xen-netfront: fix array initialization bug

vmaffione · davem330 · commit 810d8cedcc88 · 2014-04-12T16:49:06.000-04:00
This patch fixes the initialization of an array used in the TX
datapath that was mistakenly initialized together with the
RX datapath arrays. An out of range array access could happen
when RX and TX rings had different sizes.

Signed-off-by: Vincenzo Maffione &lt;v.maffione@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
@@ -1291,13 +1291,13 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev)
 	for (i = 0; i < NET_TX_RING_SIZE; i++) {
 		skb_entry_set_link(&np->tx_skbs[i], i+1);
 		np->grant_tx_ref[i] = GRANT_INVALID_REF;
+		np->grant_tx_page[i] = NULL;
 	}
 
 	/* Clear out rx_skbs */
 	for (i = 0; i < NET_RX_RING_SIZE; i++) {
 		np->rx_skbs[i] = NULL;
 		np->grant_rx_ref[i] = GRANT_INVALID_REF;
-		np->grant_tx_page[i] = NULL;
 	}
 
 	/* A grant for every tx ring slot */

Original file line number	Diff line number	Diff line change
`@@ -1291,13 +1291,13 @@ static struct net_device xennet_create_dev(struct xenbus_device dev)`
`1291`	`1291`	`for (i = 0; i < NET_TX_RING_SIZE; i++) {`
`1292`	`1292`	`skb_entry_set_link(&np->tx_skbs[i], i+1);`
`1293`	`1293`	`np->grant_tx_ref[i] = GRANT_INVALID_REF;`
	`1294`	`+ np->grant_tx_page[i] = NULL;`
`1294`	`1295`	`}`
`1295`	`1296`
`1296`	`1297`	`/* Clear out rx_skbs */`
`1297`	`1298`	`for (i = 0; i < NET_RX_RING_SIZE; i++) {`
`1298`	`1299`	`np->rx_skbs[i] = NULL;`
`1299`	`1300`	`np->grant_rx_ref[i] = GRANT_INVALID_REF;`
`1300`		`- np->grant_tx_page[i] = NULL;`
`1301`	`1301`	`}`
`1302`	`1302`
`1303`	`1303`	`/* A grant for every tx ring slot */`