xen-netfront: Delete rx_refill_timer in xennet_disconnect_backend()

[ Upstream commit 74470954857c264168d2b5a113904cf0cfd27d18 ]

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>
CC: stable@vger.kernel.org
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index fd51626e859e48f9a094e841011689b2f637b81d..ea1be52f5515664f16b2f719c40d210355dabb20 100644 (file)
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1344,6 +1344,8 @@ static void xennet_disconnect_backend(struct netfront_info *info)
        for (i = 0; i < num_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)) {
@@ -1699,7 +1701,6 @@ 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);
        }