Commit 0ee1f473 authored Jun 25, 2018 by Jiri Slaby Committed by David S. Miller Jun 26, 2018

r8152: napi hangup fix after disconnect



When unplugging an r8152 adapter while the interface is UP, the NIC
becomes unusable.  usb->disconnect (aka rtl8152_disconnect) deletes
napi. Then, rtl8152_disconnect calls unregister_netdev and that invokes
netdev->ndo_stop (aka rtl8152_close). rtl8152_close tries to
napi_disable, but the napi is already deleted by disconnect above. So
the first while loop in napi_disable never finishes. This results in
complete deadlock of the network layer as there is rtnl_mutex held by
unregister_netdev.

So avoid the call to napi_disable in rtl8152_close when the device is
already gone.

The other calls to usb_kill_urb, cancel_delayed_work_sync,
netif_stop_queue etc. seem to be fine. The urb and netdev is not
destroyed yet.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: linux-usb@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 6f0d349d

drivers/net/usb/r8152.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -3962,6 +3962,7 @@ static int rtl8152_close(struct net_device *netdev)
		#ifdef CONFIG_PM_SLEEP
		unregister_pm_notifier(&tp->pm_notifier);
		#endif
		if (!test_bit(RTL8152_UNPLUG, &tp->flags))
		napi_disable(&tp->napi);
		clear_bit(WORK_ENABLE, &tp->flags);
		usb_kill_urb(tp->intr_urb);

Admin message