Commit 58a54b9c authored by Arthur Kiyanovski's avatar Arthur Kiyanovski Committed by David S. Miller
Browse files

net: ena: fix crash during ena_remove() 



In ena_remove() we have the following stack call:
ena_remove()
  unregister_netdev()
  ena_destroy_device()
    netif_carrier_off()

Calling netif_carrier_off() causes linkwatch to try to handle the
link change event on the already unregistered netdev, which leads
to a read from an unreadable memory address.

This patch switches the order of the two functions, so that
netif_carrier_off() is called on a regiestered netdev.

To accomplish this fix we also had to:
1. Remove the set bit ENA_FLAG_TRIGGER_RESET
2. Add a sanitiy check in ena_close()
both to prevent double device reset (when calling unregister_netdev()
ena_close is called, but the device was already deleted in
ena_destroy_device()).
3. Set the admin_queue running state to false to avoid using it after
device was reset (for example when calling ena_destroy_all_io_queues()
right after ena_com_dev_reset() in ena_down)

Fixes: 944b28aa ("net: ena: fix missing lock during device destruction")
Signed-off-by: default avatarArthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e76ad21d

drivers/net/ethernet/amazon/ena/ena_netdev.c

+10 −11
Original line number Diff line number Diff line
@@ -1848,6 +1848,8 @@ static void ena_down(struct ena_adapter *adapter) 
		rc = ena_com_dev_reset(adapter->ena_dev, adapter->reset_reason);

		if (rc)

			dev_err(&adapter->pdev->dev, "Device reset failed\n");

		/* stop submitting admin commands on a device that was reset */

		ena_com_set_admin_running_state(adapter->ena_dev, false);

	}



	ena_destroy_all_io_queues(adapter);
@@ -1914,6 +1916,9 @@ static int ena_close(struct net_device *netdev) 


	netif_dbg(adapter, ifdown, netdev, "%s\n", __func__);



	if (!test_bit(ENA_FLAG_DEVICE_RUNNING, &adapter->flags))

		return 0;



	if (test_bit(ENA_FLAG_DEV_UP, &adapter->flags))

		ena_down(adapter);
@@ -2613,9 +2618,7 @@ static void ena_destroy_device(struct ena_adapter *adapter, bool graceful) 
		ena_down(adapter);



	/* Stop the device from sending AENQ events (in case reset flag is set

	 *  and device is up, ena_close already reset the device

	 * In case the reset flag is set and the device is up, ena_down()

	 * already perform the reset, so it can be skipped.

	 *  and device is up, ena_down() already reset the device.

	 */

	if (!(test_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags) && dev_up))

		ena_com_dev_reset(adapter->ena_dev, adapter->reset_reason);
@@ -3452,6 +3455,8 @@ err_rss: 
	ena_com_rss_destroy(ena_dev);

err_free_msix:

	ena_com_dev_reset(ena_dev, ENA_REGS_RESET_INIT_ERR);

	/* stop submitting admin commands on a device that was reset */

	ena_com_set_admin_running_state(ena_dev, false);

	ena_free_mgmnt_irq(adapter);

	ena_disable_msix(adapter);

err_worker_destroy:
@@ -3498,18 +3503,12 @@ static void ena_remove(struct pci_dev *pdev) 


	cancel_work_sync(&adapter->reset_task);



	unregister_netdev(netdev);



	/* If the device is running then we want to make sure the device will be

	 * reset to make sure no more events will be issued by the device.

	 */

	if (test_bit(ENA_FLAG_DEVICE_RUNNING, &adapter->flags))

		set_bit(ENA_FLAG_TRIGGER_RESET, &adapter->flags);



	rtnl_lock();

	ena_destroy_device(adapter, true);

	rtnl_unlock();



	unregister_netdev(netdev);



	free_netdev(netdev);



	ena_com_rss_destroy(ena_dev);

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