Re: [PATCH] Input: yealink - stop URB resubmission on completion error

[Dmitry Torokhov]

Hi Jie,

On Tue, Jun 16, 2026 at 11:04:40AM +0000, Jie Wang wrote:
> urb_irq_callback() and urb_ctl_callback() resubmit each other's URBs
> regardless of completion status. When the device returns a persistent
> error (-EPROTO), this creates an unthrottled resubmission loop that
> starves the CPU and triggers RCU stalls.
> 
> Stop resubmitting on any non-zero URB status, following the standard
> completion pattern used by other USB input drivers.
> 
> Reported-by: syzbot+039eab266c6321a174bd@xxxxxxxxxxxxxxxxxxxxxxxxx
> Closes: https://syzkaller.appspot.com/bug?extid=039eab266c6321a174bd
> Signed-off-by: Jie Wang <jie.wang@xxxxxxxxx>

It would be good to have a helper like

bool usb_is_permanent_error(struct urb *urb, struct device *dev);

instead of having this "switch" in all the drivers. It also unclear
whether we should not attempt to re-submit the URB on errors other than
ECONNRESET, ENOENT, or ESHUTDOWN.

> ---
>  drivers/input/misc/yealink.c | 26 ++++++++++++++++++++++----
>  1 file changed, 22 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/input/misc/yealink.c b/drivers/input/misc/yealink.c
> index 8786ed8b3565..bbfa1a9c23d1 100644
> --- a/drivers/input/misc/yealink.c
> +++ b/drivers/input/misc/yealink.c
> @@ -414,9 +414,20 @@ static void urb_irq_callback(struct urb *urb)
>  	struct yealink_dev *yld = urb->context;
>  	int ret, status = urb->status;
> 
> -	if (status)
> +	switch (status) {
> +	case 0:
> +		break;
> +	case -ECONNRESET:
> +	case -ENOENT:
> +	case -ESHUTDOWN:
> +		dev_dbg(&yld->intf->dev, "%s - urb shutting down with status %d\n",
> +			__func__, status);
> +		return;
> +	default:
>  		dev_err(&yld->intf->dev, "%s - urb status %d\n",
>  			__func__, status);
> +		return;
> +	}
> 
>  	switch (yld->irq_data->cmd) {
>  	case CMD_KEYPRESS:
> @@ -452,9 +463,20 @@ static void urb_ctl_callback(struct urb *urb)
>  	struct yealink_dev *yld = urb->context;
>  	int ret = 0, status = urb->status;
> 
> -	if (status)
> +	switch (status) {
> +	case 0:
> +		break;
> +	case -ECONNRESET:
> +	case -ENOENT:
> +	case -ESHUTDOWN:
> +		dev_dbg(&yld->intf->dev, "%s - urb shutting down with status %d\n",
> +			__func__, status);
> +		return;
> +	default:
>  		dev_err(&yld->intf->dev, "%s - urb status %d\n",
>  			__func__, status);
> +		return;
> +	}
> 
>  	switch (yld->ctl_data->cmd) {
>  	case CMD_KEYPRESS:
> --
> 2.34.1

Thanks.

-- 
Dmitry