iavf: Detach device during reset task

iavf_reset_task() takes crit_lock at the beginning and holds
it during whole call. The function subsequently calls
iavf_init_interrupt_scheme() that grabs RTNL. Problem occurs
when userspace initiates during the reset task any ndo callback
that runs under RTNL like iavf_open() because some of that
functions tries to take crit_lock. This leads to classic A-B B-A
deadlock scenario.

To resolve this situation the device should be detached in
iavf_reset_task() prior taking crit_lock to avoid subsequent
ndos running under RTNL and reattach the device at the end.

Fixes: 62fe2a865e6d ("i40evf: add missing rtnl_lock() around i40evf_set_interrupt_capability")
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Patryk Piotrowski <patryk.piotrowski@intel.com>
Cc: SlawomirX Laba <slawomirx.laba@intel.com>
Tested-by: Vitaly Grinberg <vgrinber@redhat.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index f39440ad5c50d6c07e055c145a4ec66e2a293e2f..10aa99dfdcdb05749dff5c57470ff38287d893a9 100644 (file)
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -2877,6 +2877,11 @@ static void iavf_reset_task(struct work_struct *work)
        int i = 0, err;
        bool running;
 
+       /* Detach interface to avoid subsequent NDO callbacks */
+       rtnl_lock();
+       netif_device_detach(netdev);
+       rtnl_unlock();
+
        /* When device is being removed it doesn't make sense to run the reset
         * task, just return in such a case.
         */
@@ -2884,7 +2889,7 @@ static void iavf_reset_task(struct work_struct *work)
                if (adapter->state != __IAVF_REMOVE)
                        queue_work(iavf_wq, &adapter->reset_task);
 
-               return;
+               goto reset_finish;
        }
 
        while (!mutex_trylock(&adapter->client_lock))
@@ -2954,7 +2959,6 @@ continue_reset:
 
        if (running) {
                netif_carrier_off(netdev);
-               netif_tx_stop_all_queues(netdev);
                adapter->link_up = false;
                iavf_napi_disable_all(adapter);
        }
@@ -3084,7 +3088,7 @@ continue_reset:
        mutex_unlock(&adapter->client_lock);
        mutex_unlock(&adapter->crit_lock);
 
-       return;
+       goto reset_finish;
 reset_err:
        if (running) {
                set_bit(__IAVF_VSI_DOWN, adapter->vsi.state);
@@ -3095,6 +3099,10 @@ reset_err:
        mutex_unlock(&adapter->client_lock);
        mutex_unlock(&adapter->crit_lock);
        dev_err(&adapter->pdev->dev, "failed to allocate resources during reinit\n");
+reset_finish:
+       rtnl_lock();
+       netif_device_attach(netdev);
+       rtnl_unlock();
 }
 
 /**