APPLIED(XBC, NOT D): [SRU][XBCD][PATCH] UBUNTU: SAUCE: net: ena: fix crash during ena_remove()

[Khaled Elmously]

Just to clarify, this was applied to XBC but NOT Disco



On 2018-11-09 11:12:45 , Khaled Elmously wrote:
> On 2018-11-08 10:37:58 , Kamal Mostafa wrote:
> > From: Arthur Kiyanovski <akiyano at amazon.com>
> > 
> > BugLink: http://bugs.launchpad.net/bugs/1802341
> > 
> > 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)
> > 
> > Finally, driver version is also updated.
> > 
> > Change-Id: I3cc1aafe9cb3701a6eaee44e00add0e175c93148
> > 
> > Signed-off-by: Arthur Kiyanovski <akiyano at amazon.com>
> > Signed-off-by: Kamal Mostafa <kamal at canonical.com>
> > ---
> >  drivers/net/ethernet/amazon/ena/ena_netdev.c | 21 ++++++++++-----------
> >  drivers/net/ethernet/amazon/ena/ena_netdev.h |  2 +-
> >  2 files changed, 11 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
> > index 7739cca..08a05f3 100644
> > --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
> > +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
> > @@ -1849,6 +1849,8 @@ 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);
> > @@ -1915,6 +1917,9 @@ 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:
> > @@ -3524,18 +3529,12 @@ 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);
> > diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.h b/drivers/net/ethernet/amazon/ena/ena_netdev.h
> > index 5218736..dc8b617 100644
> > --- a/drivers/net/ethernet/amazon/ena/ena_netdev.h
> > +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.h
> > @@ -45,7 +45,7 @@
> >  
> >  #define DRV_MODULE_VER_MAJOR	2
> >  #define DRV_MODULE_VER_MINOR	0
> > -#define DRV_MODULE_VER_SUBMINOR 1
> > +#define DRV_MODULE_VER_SUBMINOR 2
> >  
> >  #define DRV_MODULE_NAME		"ena"
> >  #ifndef DRV_MODULE_VERSION
> > -- 
> > 2.7.4
> > 
> > 
> > -- 
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