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

[Sergei Temerkhanov]

This may happen when, for example, one tries to get a single binary for
similar systems where those controllers may or may not present.

Regards,
Sergey

On Fri, Aug 14, 2015 at 3:15 PM, Marek Vasut <marex at denx.de> wrote:

> On Friday, August 14, 2015 at 02:13:06 PM, Sergey Temerkhanov wrote:
> > This patch fixes a potential NULL pointer dereference arising on
> > non-present/non-initialized xHCI controllers
>
> Hi,
>
> can you please explain how can such a condition even happen ?
> I believe the hcor must always be inited at that point. What
> is the condition which triggers this ?
>
> > Signed-off-by: Sergey Temerkhanov <s.temerkhanov at gmail.com>
> > Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla at cavium.com>
> > ---
> >
> >  drivers/usb/host/xhci.c | 10 ++++++----
> >  1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> > index 0b09643..a6c6659 100644
> > --- a/drivers/usb/host/xhci.c
> > +++ b/drivers/usb/host/xhci.c
> > @@ -199,7 +199,7 @@ int xhci_reset(struct xhci_hcor *hcor)
> >       int ret;
> >
> >       /* Halting the Host first */
> > -     debug("// Halt the HC\n");
> > +     debug("// Halt the HC: %p\n", hcor);
> >       state = xhci_readl(&hcor->or_usbsts) & STS_HALT;
> >       if (!state) {
> >               cmd = xhci_readl(&hcor->or_usbcmd);
> > @@ -1093,9 +1093,11 @@ int usb_lowlevel_stop(int index)
> >  {
> >       struct xhci_ctrl *ctrl = (xhcic + index);
> >
> > -     xhci_lowlevel_stop(ctrl);
> > -     xhci_hcd_stop(index);
> > -     xhci_cleanup(ctrl);
> > +     if (ctrl->hcor) {
> > +             xhci_lowlevel_stop(ctrl);
> > +             xhci_hcd_stop(index);
> > +             xhci_cleanup(ctrl);
> > +     }
> >
> >       return 0;
> >  }
>
> Best regards,
> Marek Vasut
>