ixgbe: fix panic when using macvlan with l2-fwd-offload enabled

Fix NULL pointer dereference in the case where a macvlan interface is
brought up while the PF is still down:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: [<ffffffffa0170fb2>] ixgbe_alloc_rx_buffers+0x42/0x1a0 [ixgbe]

Call Trace:
[<ffffffffa017336b>] ixgbe_configure_rx_ring+0x2eb/0x3d0 [ixgbe]
[<ffffffffa0173811>] ixgbe_fwd_ring_up+0xd1/0x380 [ixgbe]
[<ffffffffa0179709>] ixgbe_fwd_add+0x149/0x230 [ixgbe]
[<ffffffffa0113480>] macvlan_open+0x260/0x2b0 [macvlan]

Reported-by: Matthew Garrett <mjg59@coreos.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index a244d9a..bd93d82 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -9135,10 +9135,14 @@ static void *ixgbe_fwd_add(struct net_device *pdev, struct net_device *vdev)
                goto fwd_add_err;
        fwd_adapter->pool = pool;
        fwd_adapter->real_adapter = adapter;
-       err = ixgbe_fwd_ring_up(vdev, fwd_adapter);
-       if (err)
-               goto fwd_add_err;
-       netif_tx_start_all_queues(vdev);
+
+       if (netif_running(pdev)) {
+               err = ixgbe_fwd_ring_up(vdev, fwd_adapter);
+               if (err)
+                       goto fwd_add_err;
+               netif_tx_start_all_queues(vdev);
+       }
+
        return fwd_adapter;
 fwd_add_err:
        /* unwind counter and free adapter struct */