Hi,
On 10 October 2017 at 01:23, Bin Liu <b-liu@xxxxxx> wrote:
> 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@xxxxxxxxxxxxxxx # v4.3+
>> Signed-off-by: Jonathan Liu <net147@xxxxxxxxx>
>> ---
>> 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.
>
devm_usb_put_phy does solve the issue without changes in
sunxi_musb_probe but I think it is clearer that the lifetime is
explicitly managed if we don't mix implicit and explicit freeing of
resources.
>> +
>> 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.
Regards,
Jonathan
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