Re: [PATCH] usb: host: xhci-pci: Fix NULL pointer dereference error

[Mathias Nyman]

On 26.05.2015 17:15, Roger Quadros wrote:
> From: Kishon Vijay Abraham I <kishon@xxxxxx>
> 
> commit 3b8295d5cbf2 (usb: xhci: Fix suspend/resume when used
> with OTG core) removes assigning xhci->main_hcd from xhci_gen_setup
> and adds it in the probe of xhci-plat and xhci-pci.
> 
> In the case of xhci-pci, xhci_mem_init is invoked before main_hcd is
> initialized in the probe causing a null pointer deferencing error
> when a PCIe usb controller card is plugged in.
> 
> Fix it by initializing xhci->main_hcd in xhci_gen_setup and removing
> it from xhci_pci_probe().
> 
> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
> Acked-by: Roger Quadros <rogerq@xxxxxx>
> ---
> 
>  drivers/usb/host/xhci-pci.c |    1 -
>  drivers/usb/host/xhci.c     |    1 +
>  2 files changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
> index 11f16cb..67b9529 100644
> --- a/drivers/usb/host/xhci-pci.c
> +++ b/drivers/usb/host/xhci-pci.c
> @@ -230,7 +230,6 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>      /* USB 2.0 roothub is stored in the PCI device now. */
>      hcd = dev_get_drvdata(&dev->dev);
>      xhci = hcd_to_xhci(hcd);
> -    xhci->main_hcd = hcd;
>      xhci->shared_hcd = usb_create_shared_hcd(driver, &dev->dev,
>                  pci_name(dev), hcd);
>      if (!xhci->shared_hcd) {
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 397c0dd..b14f572 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -4842,6 +4842,7 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
>           */
>          hcd->speed = HCD_USB2;
>          hcd->self.root_hub->speed = USB_SPEED_HIGH;
> +        xhci->main_hcd = hcd;
>          /*
>           * USB 2.0 roothub under xHCI has an integrated TT,
>           * (rate matching hub) as opposed to having an OHCI/UHCI

Thanks, 
As your original patch causing this isn't out yet I'll undo this part from your 5/5 patch.
(prevent broken xhci for some unlucky bisecter)

-Mathias
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