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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: 944b28aa29 ("net: ena: fix missing lock during device destruction")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Arthur Kiyanovski 2018-11-19 12:05:21 +02:00 committed by David S. Miller
parent e76ad21d07
commit 58a54b9c62
1 changed files with 10 additions and 11 deletions
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21
drivers/net/ethernet/amazon/ena/ena_netdev.c
View File

@ -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 @@ static int ena_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
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);