netdev - Re: Deadlock in pciehp on dock disconnect

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Message-ID: <4c11ca11-8585-4cb5-bd0e-cd67eb1c208f@gmail.com>
Date: Fri, 5 Apr 2024 22:16:56 +0200
From: Heiner Kallweit <hkallweit1@...il.com>
To: Lukas Wunner <lukas@...ner.de>
Cc: Roman Lozko <lozko.roma@...il.com>, linux-pci@...r.kernel.org,
 Bjorn Helgaas <bhelgaas@...gle.com>,
 Dave Hansen <dave.hansen@...ux.intel.com>,
 Sean Christopherson <seanjc@...gle.com>,
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
 netdev@...r.kernel.org, Christian Marangi <ansuelsmth@...il.com>,
 Kurt Kanzenbach <kurt@...utronix.de>,
 Jesse Brandeburg <jesse.brandeburg@...el.com>,
 Tony Nguyen <anthony.l.nguyen@...el.com>, intel-wired-lan@...ts.osuosl.org
Subject: Re: Deadlock in pciehp on dock disconnect

On 05.04.2024 21:16, Lukas Wunner wrote:
> On Fri, Apr 05, 2024 at 07:48:08PM +0200, Lukas Wunner wrote:
>> Roman, does the below patch fix the issue?
> 
> Actually the patch in my previous e-mail was crap as the unregistering
> of the LEDs happened after unbind of the pdev, i.e. after
> igc_release_hw_control() and pci_disable_device().
> 
For r8169 the first version is sufficient because everything is
device-managed.

> The driver otherwise doesn't seem to be using devm_*() and with
> devm_*() it's always all or nothing.  A mix of devm_*() and manual
> teardown is prone to ordering issues.
> 
> Here's another attempt:
> 
> -- >8 --
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
> index 90316dc58630..f9ffe9df9a96 100644
> --- a/drivers/net/ethernet/intel/igc/igc.h
> +++ b/drivers/net/ethernet/intel/igc/igc.h
> @@ -298,6 +298,7 @@ struct igc_adapter {
>  
>  	/* LEDs */
>  	struct mutex led_mutex;
> +	struct igc_led_classdev *leds;
>  };
>  
>  void igc_up(struct igc_adapter *adapter);
> @@ -723,6 +724,7 @@ void igc_ptp_read(struct igc_adapter *adapter, struct timespec64 *ts);
>  void igc_ptp_tx_tstamp_event(struct igc_adapter *adapter);
>  
>  int igc_led_setup(struct igc_adapter *adapter);
> +void igc_led_teardown(struct igc_adapter *adapter);
>  
>  #define igc_rx_pg_size(_ring) (PAGE_SIZE << igc_rx_pg_order(_ring))
>  
> diff --git a/drivers/net/ethernet/intel/igc/igc_leds.c b/drivers/net/ethernet/intel/igc/igc_leds.c
> index bf240c5daf86..4c2806c0878a 100644
> --- a/drivers/net/ethernet/intel/igc/igc_leds.c
> +++ b/drivers/net/ethernet/intel/igc/igc_leds.c
> @@ -236,8 +236,8 @@ static void igc_led_get_name(struct igc_adapter *adapter, int index, char *buf,
>  		 pci_dev_id(adapter->pdev), index);
>  }
>  
> -static void igc_setup_ldev(struct igc_led_classdev *ldev,
> -			   struct net_device *netdev, int index)
> +static int igc_setup_ldev(struct igc_led_classdev *ldev,
> +			  struct net_device *netdev, int index)
>  {
>  	struct igc_adapter *adapter = netdev_priv(netdev);
>  	struct led_classdev *led_cdev = &ldev->led;
> @@ -257,15 +257,15 @@ 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);
> +	return led_classdev_register(&netdev->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;
> +	int i, ret;
>  
>  	mutex_init(&adapter->led_mutex);
>  
> @@ -273,8 +273,27 @@ int igc_led_setup(struct igc_adapter *adapter)
>  	if (!leds)
>  		return -ENOMEM;
>  
> -	for (i = 0; i < IGC_NUM_LEDS; i++)
> -		igc_setup_ldev(leds + i, netdev, i);
> +	for (i = 0; i < IGC_NUM_LEDS; i++) {
> +		ret = igc_setup_ldev(leds + i, netdev, i);
> +		if (ret)
> +			goto err;
> +	}
> +
> +	adapter->leds = leds;
>  
>  	return 0;
> +
> +err:
> +	for (i--; i >= 0; i--)
> +		led_classdev_unregister(&((leds + i)->led));
> +	return ret;
> +}
> +
> +void igc_led_teardown(struct igc_adapter *adapter)
> +{
> +	struct igc_led_classdev *leds = adapter->leds;
> +	int i;
> +
> +	for (i = 0; i < IGC_NUM_LEDS; i++)
> +		led_classdev_unregister(&((leds + i)->led));
>  }
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
> index 2e1cfbd82f4f..cd164442ab35 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -7025,6 +7025,9 @@ static void igc_remove(struct pci_dev *pdev)
>  	cancel_work_sync(&adapter->watchdog_task);
>  	hrtimer_cancel(&adapter->hrtimer);
>  
> +	if (IS_ENABLED(CONFIG_IGC_LEDS))
> +		igc_led_teardown(adapter);
> +
>  	/* Release control of h/w to f/w.  If f/w is AMT enabled, this
>  	 * would have already happened in close and is redundant.
>  	 */
>