[PATCH 5.11 069/122] ixgbe: Fix NULL pointer dereference in ethtool loopback test

[Greg Kroah-Hartman]

From: Alexander Duyck <alexanderduyck@xxxxxx>

commit 31166efb1cee348eb6314e9c0095d84cbeb66b9d upstream.

The ixgbe driver currently generates a NULL pointer dereference when
performing the ethtool loopback test. This is due to the fact that there
isn't a q_vector associated with the test ring when it is setup as
interrupts are not normally added to the test rings.

To address this I have added code that will check for a q_vector before
returning a napi_id value. If a q_vector is not present it will return a
value of 0.

Fixes: b02e5a0ebb17 ("xsk: Propagate napi_id to XDP socket Rx path")
Signed-off-by: Alexander Duyck <alexanderduyck@xxxxxx>
Acked-by: Björn Töpel <bjorn.topel@xxxxxxxxx>
Tested-by: Dave Switzer <david.switzer@xxxxxxxxx>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -6540,6 +6540,13 @@ err_setup_tx:
 	return err;
 }
 
+static int ixgbe_rx_napi_id(struct ixgbe_ring *rx_ring)
+{
+	struct ixgbe_q_vector *q_vector = rx_ring->q_vector;
+
+	return q_vector ? q_vector->napi.napi_id : 0;
+}
+
 /**
  * ixgbe_setup_rx_resources - allocate Rx resources (Descriptors)
  * @adapter: pointer to ixgbe_adapter
@@ -6587,7 +6594,7 @@ int ixgbe_setup_rx_resources(struct ixgb
 
 	/* XDP RX-queue info */
 	if (xdp_rxq_info_reg(&rx_ring->xdp_rxq, adapter->netdev,
-			     rx_ring->queue_index, rx_ring->q_vector->napi.napi_id) < 0)
+			     rx_ring->queue_index, ixgbe_rx_napi_id(rx_ring)) < 0)
 		goto err;
 
 	rx_ring->xdp_prog = adapter->xdp_prog;