From: Jiri Slaby Date: Mon, 25 Jun 2018 07:26:27 +0000 (+0200) Subject: r8152: napi hangup fix after disconnect X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=0ee1f4734967af8321ecebaf9c74221ace34f2d5;p=openwrt%2Fstaging%2Fblogic.git 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 Cc: linux-usb@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller --- diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c index 86f7196f9d91..2a58607a6aea 100644 --- a/drivers/net/usb/r8152.c +++ b/drivers/net/usb/r8152.c @@ -3962,7 +3962,8 @@ static int rtl8152_close(struct net_device *netdev) #ifdef CONFIG_PM_SLEEP unregister_pm_notifier(&tp->pm_notifier); #endif - napi_disable(&tp->napi); + if (!test_bit(RTL8152_UNPLUG, &tp->flags)) + napi_disable(&tp->napi); clear_bit(WORK_ENABLE, &tp->flags); usb_kill_urb(tp->intr_urb); cancel_delayed_work_sync(&tp->schedule);