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

[Marek Vasut]

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 ?