e1000: Hold RTNL when e1000_down can be called

e1000_down calls netif_queue_set_napi, which assumes that RTNL is held.

There are a few paths for e1000_down to be called in e1000 where RTNL is
not currently being held:
  - e1000_shutdown (pci shutdown)
  - e1000_suspend (power management)
  - e1000_reinit_locked (via e1000_reset_task delayed work)
  - e1000_io_error_detected (via pci error handler)

Hold RTNL in three places to fix this issue:
  - e1000_reset_task: igc, igb, and e100e all hold rtnl in this path.
  - e1000_io_error_detected (pci error handler): e1000e and ixgbe hold
    rtnl in this path. A patch has been posted for igc to do the same
    [1].
  - __e1000_shutdown (which is called from both e1000_shutdown and
    e1000_suspend): igb, ixgbe, and e1000e all hold rtnl in the same
    path.

The other paths which call e1000_down seemingly hold RTNL and are OK:
  - e1000_close (ndo_stop)
  - e1000_change_mtu (ndo_change_mtu)

Based on the above analysis and mailing list discussion [2], I believe
adding rtnl in the three places mentioned above is correct.

Fixes: 8f7ff18a5ec7 ("e1000: Link NAPI instances to queues and IRQs")
Reported-by: Dmitry Antipov <dmantipov@yandex.ru>
Closes: https://lore.kernel.org/netdev/8cf62307-1965-46a0-a411-ff0080090ff9@yandex.ru/
Link: https://lore.kernel.org/netdev/20241022215246.307821-3-jdamato@fastly.com/
Link: https://lore.kernel.org/netdev/ZxgVRX7Ne-lTjwiJ@LQ3V64L9R2/
Signed-off-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 4de9b156b2bea012358e6b4076f4fa7ceb9fb2e9..3f089c3d47b23b9e5c040de110d6e92df6820c01 100644 (file)
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -3509,7 +3509,9 @@ static void e1000_reset_task(struct work_struct *work)
                container_of(work, struct e1000_adapter, reset_task);
 
        e_err(drv, "Reset adapter\n");
+       rtnl_lock();
        e1000_reinit_locked(adapter);
+       rtnl_unlock();
 }
 
 /**
@@ -5074,7 +5076,9 @@ static int __e1000_shutdown(struct pci_dev *pdev, bool *enable_wake)
                        usleep_range(10000, 20000);
 
                WARN_ON(test_bit(__E1000_RESETTING, &adapter->flags));
+               rtnl_lock();
                e1000_down(adapter);
+               rtnl_unlock();
        }
 
        status = er32(STATUS);
@@ -5235,16 +5239,20 @@ static pci_ers_result_t e1000_io_error_detected(struct pci_dev *pdev,
        struct net_device *netdev = pci_get_drvdata(pdev);
        struct e1000_adapter *adapter = netdev_priv(netdev);
 
+       rtnl_lock();
        netif_device_detach(netdev);
 
-       if (state == pci_channel_io_perm_failure)
+       if (state == pci_channel_io_perm_failure) {
+               rtnl_unlock();
                return PCI_ERS_RESULT_DISCONNECT;
+       }
 
        if (netif_running(netdev))
                e1000_down(adapter);
 
        if (!test_and_set_bit(__E1000_DISABLED, &adapter->flags))
                pci_disable_device(pdev);
+       rtnl_unlock();
 
        /* Request a slot reset. */
        return PCI_ERS_RESULT_NEED_RESET;