On Fri, Apr 05, 2024 at 03:31:34PM +0200, Heiner Kallweit wrote: > On 05.04.2024 12:02, Lukas Wunner wrote: > > On Fri, Apr 05, 2024 at 11:14:01AM +0200, Roman Lozko wrote: > > > Hi, I'm using HP G4 Thunderbolt docking station, and recently (?) > > > kernel started to "partially" deadlock after disconnecting the dock > > > station. This results in inability to turn network interfaces on or > > > off, system can't reboot, `sudo` does not work (guess because it uses > > > DNS). > > > > unregister_netdev() acquires rtnl_lock(), indirectly invokes > > netdev_trig_deactivate() upon unregistering some LED, thereby > > calling unregister_netdevice_notifier(), which tries to > > acquire rtnl_lock() again. > > > > From a quick look at the source files involved, this doesn't look > > like something new, though I note LED support for igc was added > > only recently with ea578703b03d ("igc: Add support for LEDs on > > i225/i226"), which went into v6.9-rc1. > > It's unfortunate that the device-managed LED is bound to the netdev device. > Wouldn't binding it to the parent (&pdev->dev) solve the issue? I'm guessing igc commit ea578703b03d copy-pasted from r8169 commit be51ed104ba9 ("r8169: add LED support for RTL8125/RTL8126") because that driver has exactly the same problem. :) Roman, does the below patch fix the issue? Note that just changing the devm_led_classdev_register() call isn't sufficient: I'm changing the devm_kcalloc() in igc_led_setup() as well to avoid a use-after-free (memory would already get freed on netdev unregister but led a little later on pdev unbind). -- >8 -- diff --git a/drivers/net/ethernet/intel/igc/igc_leds.c b/drivers/net/ethernet/intel/igc/igc_leds.c index bf240c5..0b78c30 100644 --- a/drivers/net/ethernet/intel/igc/igc_leds.c +++ b/drivers/net/ethernet/intel/igc/igc_leds.c @@ -257,13 +257,13 @@ static void igc_setup_ldev(struct igc_led_classdev *ldev, led_cdev->hw_control_get = igc_led_hw_control_get; led_cdev->hw_control_get_device = igc_led_hw_control_get_device; - devm_led_classdev_register(&netdev->dev, led_cdev); + devm_led_classdev_register(&adapter->pdev->dev, led_cdev); } int igc_led_setup(struct igc_adapter *adapter) { struct net_device *netdev = adapter->netdev; - struct device *dev = &netdev->dev; + struct device *dev = &adapter->pdev->dev; struct igc_led_classdev *leds; int i;