Re: [PATCH v1 1/1] usb: dwc3: Fix NULL pointer exception in dwc3_pci_remove()

[sathyanarayanan kuppuswamy]

Felipe/Greg,

Any comments ?

On 10/17/18 11:40 AM, Kuppuswamy Sathyanarayanan wrote:
> In dwc3_pci_quirks() function, gpiod lookup table is only registered for
> baytrail SOC. But in dwc3_pci_remove(), we try to unregistered it
> without any checks. This leads to NULL pointer de-reference exception in
> gpiod_remove_lookup_table() when unloading the module for non baytrail
> SOCs. This patch fixes this issue.
>
> Fixes: 5741022cbdf3 ("usb: dwc3: pci: Add GPIO lookup table on platforms
> without ACPI GPIO resources")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
>   drivers/usb/dwc3/dwc3-pci.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/dwc3-pci.c b/drivers/usb/dwc3/dwc3-pci.c
> index 1286076a8890..842795856bf4 100644
> --- a/drivers/usb/dwc3/dwc3-pci.c
> +++ b/drivers/usb/dwc3/dwc3-pci.c
> @@ -283,8 +283,10 @@ static int dwc3_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
>   static void dwc3_pci_remove(struct pci_dev *pci)
>   {
>   	struct dwc3_pci		*dwc = pci_get_drvdata(pci);
> +	struct pci_dev		*pdev = dwc->pci;
>   
> -	gpiod_remove_lookup_table(&platform_bytcr_gpios);
> +	if (pdev->device == PCI_DEVICE_ID_INTEL_BYT)
> +		gpiod_remove_lookup_table(&platform_bytcr_gpios);
>   #ifdef CONFIG_PM
>   	cancel_work_sync(&dwc->wakeup_work);
>   #endif

--
Sathyanarayanan Kuppuswamy
Linux kernel developer