From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marex@denx.de>
Date: Fri, 14 Aug 2015 16:45:56 +0200
Subject: [U-Boot] [PATCH] usb: xhci: Fix a potential NULL pointer
	dereference
In-Reply-To: <CAPEA6dYdY9bEgsXGMG9ncgBd22iUVzyi5pyJGWMnAFi7fonE6A@mail.gmail.com>
References: <1439554386-9406-1-git-send-email-s.temerkhanov@gmail.com>
 <201508141544.17866.marex@denx.de>
 <CAPEA6dYdY9bEgsXGMG9ncgBd22iUVzyi5pyJGWMnAFi7fonE6A@mail.gmail.com>
Message-ID: <201508141645.56825.marex@denx.de>
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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@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 ?