Re: Null Pointer BUG in uhci_hcd

Michael S. Zick
2009-07-07T15:24:32Z

On Tue July 7 2009, Alan Stern wrote:
> On Tue, 7 Jul 2009, Oliver Neukum wrote:
>
> > Am Dienstag, 7. Juli 2009 11:13:01 schrieb Jiri Kosina:
> > > [ adding linux-usb to CC ]
> > >
> > > On Sun, 5 Jul 2009, Michael S. Zick wrote:
> > > > Anyone with suggestions about this one?
> >
> > Looks like we should test for presence before we switch off
> > autosuspend for khubd. Please test this diagnostic patch if this is
> > repeatable.
>
> That patch won't fix the problem. This issue is not that hdev is NULL;
> the problem is that the hub driver isn't bound to hdev and as a result,
> the hdev_to_hub routine fails.
>
> This patch may work better.
>

Got it.
Anything that gives me something other than a dead machine
with a glowing power-on light is forward progress.

Will give this patch a try today and report back.

At the moment am running the machine without either USB driver loaded.
Just to see if they are contributing to the problems.

Mike
> Alan Stern
>
>
> Index: usb-2.6/drivers/usb/core/hub.c
> ===================================================================
> --- usb-2.6.orig/drivers/usb/core/hub.c
> +++ usb-2.6/drivers/usb/core/hub.c
> @@ -163,8 +163,10 @@ static inline char *portspeed(int portst
> }
>
> /* Note that hdev or one of its children must be locked! */
> -static inline struct usb_hub *hdev_to_hub(struct usb_device *hdev)
> +static struct usb_hub *hdev_to_hub(struct usb_device *hdev)
> {
> + if (!hdev || !hdev->actconfig)
> + return NULL;
> return usb_get_intfdata(hdev->actconfig->interface[0]);
> }
>
> @@ -385,8 +387,10 @@ static void kick_khubd(struct usb_hub *h
>
> void usb_kick_khubd(struct usb_device *hdev)
> {
> - /* FIXME: What if hdev isn't bound to the hub driver? */
> - kick_khubd(hdev_to_hub(hdev));
> + struct usb_hub *hub = hdev_to_hub(hdev);
> +
> + if (hub)
> + kick_khubd(hub);
> }
>
>
>
>
>