igb: fix rtnl race in PM resume path
Benjamin Poirier [Thu, 10 May 2012 15:38:37 +0000 (15:38 +0000)]
Since the caller (PM resume code) is not the one holding rtnl, when taking the
'else' branch rtnl may be released at any moment, thereby defeating the whole
purpose of this code block.

Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/igb/igb_main.c

index d223500..8683ca4 100644 (file)
@@ -1111,9 +1111,12 @@ msi_only:
                adapter->flags |= IGB_FLAG_HAS_MSI;
 out:
        /* Notify the stack of the (possibly) reduced queue counts. */
+       rtnl_lock();
        netif_set_real_num_tx_queues(adapter->netdev, adapter->num_tx_queues);
-       return netif_set_real_num_rx_queues(adapter->netdev,
-                                           adapter->num_rx_queues);
+       err = netif_set_real_num_rx_queues(adapter->netdev,
+               adapter->num_rx_queues);
+       rtnl_unlock();
+       return err;
 }
 
 /**
@@ -6796,18 +6799,7 @@ static int igb_resume(struct device *dev)
        pci_enable_wake(pdev, PCI_D3hot, 0);
        pci_enable_wake(pdev, PCI_D3cold, 0);
 
-       if (!rtnl_is_locked()) {
-               /*
-                * shut up ASSERT_RTNL() warning in
-                * netif_set_real_num_tx/rx_queues.
-                */
-               rtnl_lock();
-               err = igb_init_interrupt_scheme(adapter);
-               rtnl_unlock();
-       } else {
-               err = igb_init_interrupt_scheme(adapter);
-       }
-       if (err) {
+       if (igb_init_interrupt_scheme(adapter)) {
                dev_err(&pdev->dev, "Unable to allocate memory for queues\n");
                return -ENOMEM;
        }