linux-kernel - Re: net: usb: r8152: resume-reset deadlock

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Message-ID: <glff4ejcf37b7avgqdmxbobujezchyyxhytpqoe2gskd4qlgoe@nq6tiutyc5qe>
Date: Wed, 28 Jan 2026 15:39:58 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Paolo Abeni <pabeni@...hat.com>
Cc: Andrew Lunn <andrew+netdev@...n.ch>, 
	"David S. Miller" <davem@...emloft.net>, Realtek linux nic maintainers <nic_swsd@...ltek.com>, 
	Takashi Iwai <tiwai@...e.de>, linux-usb@...r.kernel.org, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: Re: net: usb: r8152: resume-reset deadlock

On (26/01/28 15:12), Sergey Senozhatsky wrote:
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index 30f937527cd2..c9406b89bb12 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -8538,20 +8538,18 @@ static int rtl8152_system_resume(struct r8152 *tp)
>  		usb_submit_urb(tp->intr_urb, GFP_NOIO);
>  	}
>  
> +	if (!test_bit(RTL8152_INACCESSIBLE, &tp->flags))
> +		return 0;
> +
>  	/* If the device is RTL8152_INACCESSIBLE here then we should do a
>  	 * reset. This is important because the usb_lock_device_for_reset()
>  	 * that happens as a result of usb_queue_reset_device() will silently
>  	 * fail if the device was suspended or if too much time passed.
> -	 *
> -	 * NOTE: The device is locked here so we can directly do the reset.
> -	 * We don't need usb_lock_device_for_reset() because that's just a
> -	 * wrapper over device_lock() and device_resume() (which calls us)
> -	 * does that for us.
>  	 */
> -	if (test_bit(RTL8152_INACCESSIBLE, &tp->flags))
> -		usb_reset_device(tp->udev);
> +	if (test_bit(SELECTIVE_SUSPEND, &tp->flags))
> +		return usb_reset_device(tp->udev);
>  
> -	return 0;
> +	return -ENODEV;
>  }
>  
>  static int rtl8152_runtime_suspend(struct r8152 *tp)
> @@ -8674,6 +8672,14 @@ static int rtl8152_resume(struct usb_interface *intf)
>  
>  	mutex_unlock(&tp->control);
>  
> +	/*
> +	 * This only happens for !SELECTIVE_SUSPEND and RTL8152_INACCESSIBLE,
> +	 * drop tp->control, becuase reset can re-acquire it (e.g. from
> +	 * max address reset)
> +	 */
> +	if (ret == -ENODEV)
> +		ret = usb_reset_device(tp->udev);
> +
>  	return ret;
>  }

That's too messy.  Something like this should be better, I guess:

---

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 30f937527cd2..2cbc07b7aab5 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -8538,19 +8538,6 @@ static int rtl8152_system_resume(struct r8152 *tp)
 		usb_submit_urb(tp->intr_urb, GFP_NOIO);
 	}
 
-	/* If the device is RTL8152_INACCESSIBLE here then we should do a
-	 * reset. This is important because the usb_lock_device_for_reset()
-	 * that happens as a result of usb_queue_reset_device() will silently
-	 * fail if the device was suspended or if too much time passed.
-	 *
-	 * NOTE: The device is locked here so we can directly do the reset.
-	 * We don't need usb_lock_device_for_reset() because that's just a
-	 * wrapper over device_lock() and device_resume() (which calls us)
-	 * does that for us.
-	 */
-	if (test_bit(RTL8152_INACCESSIBLE, &tp->flags))
-		usb_reset_device(tp->udev);
-
 	return 0;
 }
 
@@ -8661,6 +8648,7 @@ static int rtl8152_suspend(struct usb_interface *intf, pm_message_t message)
 static int rtl8152_resume(struct usb_interface *intf)
 {
 	struct r8152 *tp = usb_get_intfdata(intf);
+	bool system_resume = !test_bit(SELECTIVE_SUSPEND, &tp->flags);
 	int ret;
 
 	mutex_lock(&tp->control);
@@ -8674,6 +8662,9 @@ static int rtl8152_resume(struct usb_interface *intf)
 
 	mutex_unlock(&tp->control);
 
+	if (system_resume && test_bit(RTL8152_INACCESSIBLE, &tp->flags))
+		ret = usb_reset_device(tp->udev);
+
 	return ret;
 }