Re: [PATCH v2] usb: dwc3: qcom: check for hcd in dwc3_qcom_read_usb2_speed

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] usb: dwc3: qcom: uninitialized udev pointer in dwc3_qcom_read_usb2_speed()
--

commit 9364e775b526fa295084d32e8e9579d5847360c6
Author: Prashanth K <prashanth.k@oss.qualcomm.com>

usb: dwc3: qcom: check for hcd in dwc3_qcom_read_usb2_speed

This commit checks whether hcd is non-NULL in dwc3_qcom_read_usb2_speed()
before dereferencing it to avoid a NULL pointer dereference during system
suspend if xhci_plat_probe() failed.

> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index ac68b4218b56b..6ca51d37c35ac 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -241,7 +241,8 @@ static enum usb_device_speed dwc3_qcom_read_usb2_speed(struct dwc3_qcom *qcom, i
>  	hcd = platform_get_drvdata(dwc->xhci);
>  
>  #ifdef CONFIG_USB
> -	udev = usb_hub_find_child(hcd->self.root_hub, port_index + 1);
> +	if (hcd)
> +		udev = usb_hub_find_child(hcd->self.root_hub, port_index + 1);
>  #else
>  	udev = NULL;
>  #endif

[Severity: High]
In drivers/usb/dwc3/dwc3-qcom.c, dwc3_qcom_read_usb2_speed() declares udev on
the stack without initializing it:

drivers/usb/dwc3/dwc3-qcom.c:dwc3_qcom_read_usb2_speed() {
	struct usb_device *udev;
	struct usb_hcd __maybe_unused *hcd;
	struct dwc3 *dwc = &qcom->dwc;

	hcd = platform_get_drvdata(dwc->xhci);

#ifdef CONFIG_USB
	if (hcd)
		udev = usb_hub_find_child(hcd->self.root_hub, port_index + 1);
#else
	udev = NULL;
#endif
	if (!udev)
		return USB_SPEED_UNKNOWN;

	return udev->speed;
}

When CONFIG_USB is enabled and platform_get_drvdata(dwc->xhci) returns NULL
during dwc3_qcom_pm_suspend() -> dwc3_qcom_read_usb2_speed() (for example,
when xhci_plat_probe() failed), won't udev remain uninitialized and cause
if (!udev) and return udev->speed to read and dereference an uninitialized
pointer?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261022044748.2303528-1-prashanth.k@oss.qualcomm.com?part=1