[PATCH] usb: musb: sunxi: Explicitly release USB PHY on exit

[Bin Liu]

Hi,

On Tue, Sep 26, 2017 at 09:39:23PM +1000, Jonathan Liu wrote:
> This fixes a kernel oops when unloading the driver due to usb_put_phy
> being called after usb_phy_generic_unregister when the device is
> detached. Calling usb_phy_generic_unregister causes x->dev->driver to
> be NULL in usb_put_phy and results in a NULL pointer dereference.
> 
> As we are now explicitly managing the lifetime of usb_phy,
> devm_usb_get_phy is changed to usb_get_phy and we call usb_put_phy in
> the probe error path.
> 
> Cc: stable at vger.kernel.org # v4.3+
> Signed-off-by: Jonathan Liu <net147 at gmail.com>
> ---
>  drivers/usb/musb/sunxi.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/musb/sunxi.c b/drivers/usb/musb/sunxi.c
> index c9a09b5bb6e5..8eed61042103 100644
> --- a/drivers/usb/musb/sunxi.c
> +++ b/drivers/usb/musb/sunxi.c
> @@ -297,6 +297,8 @@ static int sunxi_musb_exit(struct musb *musb)
>  	if (test_bit(SUNXI_MUSB_FL_HAS_SRAM, &glue->flags))
>  		sunxi_sram_release(musb->controller->parent);
>  
> +	usb_put_phy(glue->xceiv);

Will devm_usb_put_phy() solve the issue too? Then you don't need the
changes in sunxi_musb_probe() below.

> +
>  	return 0;
>  }
>  
> @@ -781,7 +783,7 @@ static int sunxi_musb_probe(struct platform_device *pdev)
>  		return PTR_ERR(glue->usb_phy);
>  	}
>  
> -	glue->xceiv = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
> +	glue->xceiv = usb_get_phy(USB_PHY_TYPE_USB2);
>  	if (IS_ERR(glue->xceiv)) {
>  		ret = PTR_ERR(glue->xceiv);
>  		dev_err(&pdev->dev, "Error getting usb-phy %d\n", ret);
> @@ -803,11 +805,13 @@ static int sunxi_musb_probe(struct platform_device *pdev)
>  	if (IS_ERR(glue->musb_pdev)) {
>  		ret = PTR_ERR(glue->musb_pdev);
>  		dev_err(&pdev->dev, "Error registering musb dev: %d\n", ret);
> -		goto err_unregister_usb_phy;
> +		goto err_put_usb_phy;
>  	}
>  
>  	return 0;
>  
> +err_put_usb_phy:
> +	usb_put_phy(glue->xceiv);
>  err_unregister_usb_phy:
>  	usb_phy_generic_unregister(glue->usb_phy);
>  	return ret;
> -- 
> 2.13.2

Regards,
-Bin.