Commit 06673c21 authored by Jan Beulich's avatar Jan Beulich Committed by Paolo Abeni
Browse files

xen-netfront: re-order error checks in xennet_get_responses() 



Check the retrieved grant reference first; there's no point trying to
have xennet_move_rx_slot() move invalid data (and further defer
recognition of the issue, likely making diagnosis yet more difficult).

Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent ad39bafd

drivers/net/xen-netfront.c

+10 −10
Original line number Diff line number Diff line
@@ -1043,16 +1043,6 @@ static int xennet_get_responses(struct netfront_queue *queue, 
	}



	for (;;) {

		if (unlikely(rx->status < 0 ||

			     rx->offset + rx->status > XEN_PAGE_SIZE)) {

			if (net_ratelimit())

				dev_warn(dev, "rx->offset: %u, size: %d\n",

					 rx->offset, rx->status);

			xennet_move_rx_slot(queue, skb, ref);

			err = -EINVAL;

			goto next;

		}



		/*

		 * This definitely indicates a bug, either in this driver or in

		 * the backend driver. In future this should flag the bad
@@ -1066,6 +1056,16 @@ static int xennet_get_responses(struct netfront_queue *queue, 
			goto next;

		}



		if (unlikely(rx->status < 0 ||

			     rx->offset + rx->status > XEN_PAGE_SIZE)) {

			if (net_ratelimit())

				dev_warn(dev, "rx->offset: %u, size: %d\n",

					 rx->offset, rx->status);

			xennet_move_rx_slot(queue, skb, ref);

			err = -EINVAL;

			goto next;

		}



		if (!gnttab_end_foreign_access_ref(ref)) {

			dev_alert(dev,

				  "Grant still in use by backend domain\n");