[U-Boot] [PATCH] usb: xhci: Fix a potential NULL pointer dereference

[Sergei Temerkhanov]

On Fri, Aug 14, 2015 at 5:45 PM, Marek Vasut <marex at denx.de> wrote:
> On Friday, August 14, 2015 at 04:29:43 PM, Sergei Temerkhanov wrote:
>> On Fri, Aug 14, 2015 at 4:44 PM, Marek Vasut <marex at denx.de> wrote:
>> > On Friday, August 14, 2015 at 03:00:31 PM, Sergei Temerkhanov wrote:
>> >> This may happen when, for example, one tries to get a single binary for
>> >> similar systems where those controllers may or may not present.
>> >
>> > Please DO STOP TOP-POSTING, I mentioned it already, it is really not
>> > helpful.
>>
>> Sorry about that, had to struggle with Gmail on my tablet.
>
> Thanks :)
>
>> > I think your patch is missing one small bit in usb_lowlevel_init() in
>> > xhci.c In case xhci_lowlevel_init() fails and thus the controller is NOT
>> > inited, the usb_lowlevel_stop() will still try to unregister such
>> > controller, which will likely fail.
>> >
>> > You might want to add a check which sets the HCOR and HCCR to NULL if the
>> > xhci_lowlevel_init() fails. What do you think ?
>>
>> Might be useful - it's more about error handling rather then core
>> configurations.
>> For the latter xhci_hcd_init() seems to be an appropriate place to set
>> hccr and hcor
>> to NULL.
>>
>> For error handling, it might be useful to modify usb_low_level_init like
>> this:
>>
>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>> index a6c6659..f8e2d70 100644
>> --- a/drivers/usb/host/xhci.c
>> +++ b/drivers/usb/host/xhci.c
>> @@ -1079,6 +1079,11 @@ int usb_lowlevel_init(int index, enum
>> usb_init_type init, void **controller)
>>
>>         *controller = &xhcic[index];
>>
>> +       if (ret) {
>> +               ctrl->hccr = NULL;
>> +               ctrl->hcor = NULL;
>> +       }
>> +
>>         return ret;
>>  }
>
> You might also want to set *controller to NULL, just to be explicitly correct.
> Can you please send a V2 patch ?

OK, in a few minutes.