[PATCH 3.16 169/366] net/xen-netfront: only clean up queues if present

Ben Hutchings
2018-11-11T20:37:11Z

From: Chas Williams <3chas3@gmail.com>

commit 9a873c71e91cabf4c10fd9bbd8358c22deaf6c9e upstream.

If you simply load and unload the module without starting the interfaces,
the queues are never created and you get a bad pointer dereference.

Signed-off-by: Chas Williams <3chas3@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/xen-netfront.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1422,7 +1422,7 @@ static void xennet_disconnect_backend(st

netif_carrier_off(info->netdev);

- for (i = 0; i < num_queues; ++i) {
+ for (i = 0; i < num_queues && info->queues; ++i) {
struct netfront_queue *queue = &info->queues[i];

del_timer_sync(&queue->rx_refill_timer);
@@ -2294,7 +2294,8 @@ static int xennet_remove(struct xenbus_d

unregister_netdev(info->netdev);

- xennet_destroy_queues(info);
+ if (info->queues)
+ xennet_destroy_queues(info);
xennet_free_netdev(info->netdev);

return 0;