xen-netfront: Delete rx_refill_timer in xennet_disconnect_backend()

commit 74470954857c264168d2b5a113904cf0cfd27d18 upstream.

rx_refill_timer should be deleted as soon as we disconnect from the
backend since otherwise it is possible for the timer to go off before
we get to xennet_destroy_queues(). If this happens we may dereference
queue->rx.sring which is set to NULL in xennet_disconnect_backend().

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index d6abf191122a3260cbd97f5c1a2dbd1c2cb5c5e2..1f445f357da115e8c644a4822912bb607cdf40c4 100644 (file)
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1391,6 +1391,8 @@ static void xennet_disconnect_backend(struct netfront_info *info)
        for (i = 0; i < num_queues && info->queues; ++i) {
                struct netfront_queue *queue = &info->queues[i];
 
+               del_timer_sync(&queue->rx_refill_timer);
+
                if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
                        unbind_from_irqhandler(queue->tx_irq, queue);
                if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
@@ -1745,7 +1747,6 @@ static void xennet_destroy_queues(struct netfront_info *info)
 
                if (netif_running(info->netdev))
                        napi_disable(&queue->napi);
-               del_timer_sync(&queue->rx_refill_timer);
                netif_napi_del(&queue->napi);
        }