Re: [PATCH] usb: fix reference leak in usb_new_device()

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Dec 17, 2024 at 11:53:52AM +0800, Ma Ke wrote:
> When device_add(&udev->dev) failed, calling put_device() to explicitly
> release udev->dev. Otherwise, it could cause double free problem.
> 
> Found by code review.
> 
> Cc: stable@vger.kernel.org
> Fixes: 9f8b17e643fe ("USB: make usbdevices export their device nodes instead of using a separate class")
> Signed-off-by: Ma Ke <make_ruc2021@163.com>
> ---
>  drivers/usb/core/hub.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 4b93c0bd1d4b..05b778d2ad63 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -2651,6 +2651,7 @@ int usb_new_device(struct usb_device *udev)
>  	err = device_add(&udev->dev);
>  	if (err) {
>  		dev_err(&udev->dev, "can't device_add, error %d\n", err);
> +		put_device(&udev->dev);
>  		goto fail;
>  	}
>  
> @@ -2683,6 +2684,9 @@ int usb_new_device(struct usb_device *udev)
>  	pm_runtime_put_sync_autosuspend(&udev->dev);
>  	return err;
>  
> +out_del_dev:
> +	device_del(&udev->dev);
> +	put_device(&udev->dev);
>  fail:
>  	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
>  	pm_runtime_disable(&udev->dev);

How was this change tested?

thanks,

greg k-h