xen-netback: free queues after freeing the net device
If a queue still has a NAPI instance added to the net device, freeing
the queues early results in a use-after-free.
The shouldn't ever happen because we disconnect and tear down all queues
before freeing the net device, but doing this makes it obviously safe.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 3bba6ce..f5231a2 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -685,22 +685,16 @@
void xenvif_free(struct xenvif *vif)
{
- struct xenvif_queue *queue = NULL;
+ struct xenvif_queue *queues = vif->queues;
unsigned int num_queues = vif->num_queues;
unsigned int queue_index;
unregister_netdev(vif->dev);
-
- for (queue_index = 0; queue_index < num_queues; ++queue_index) {
- queue = &vif->queues[queue_index];
- xenvif_deinit_queue(queue);
- }
-
- vfree(vif->queues);
- vif->queues = NULL;
- vif->num_queues = 0;
-
free_netdev(vif->dev);
+ for (queue_index = 0; queue_index < num_queues; ++queue_index)
+ xenvif_deinit_queue(&queues[queue_index]);
+ vfree(queues);
+
module_put(THIS_MODULE);
}