[PATCH] usb: dwc3: host: Mark dwc->xhci as null if xhci probe fails

[PATCH] usb: dwc3: host: Mark dwc->xhci as null if xhci probe fails

[Prashanth K]

Currently dwc->xhci is not cleared when xhci_plat_probe fails,
leading to null pointer dereference in dwc3_qcom_read_usb2_speed.
Mark the xhci pointer as NULL to prevent this.

Signed-off-by: Prashanth K <prashanth.k@oss.qualcomm.com>
---
 drivers/usb/dwc3/host.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index c5674161b2b0..b01cf49454c2 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -219,6 +219,7 @@ int dwc3_host_init(struct dwc3 *dwc)
 	return 0;
 err:
 	platform_device_put(xhci);
+	dwc->xhci = NULL;
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dwc3_host_init);
-- 
2.34.1

Re: [PATCH] usb: dwc3: host: Mark dwc->xhci as null if xhci probe fails

[Greg Kroah-Hartman]

On Wed, Oct 14, 2026 at 04:27:11PM +0530, Prashanth K wrote:
> Currently dwc->xhci is not cleared when xhci_plat_probe fails,
> leading to null pointer dereference in dwc3_qcom_read_usb2_speed.

Why would that happen?  What causes it and requires it?

> Mark the xhci pointer as NULL to prevent this.
> 
> Signed-off-by: Prashanth K <prashanth.k@oss.qualcomm.com>

What commit id does this fix?
How was it tested?

thanks,

greg k-h

Re: [PATCH] usb: dwc3: host: Mark dwc->xhci as null if xhci probe fails

[Prashanth K]

On 10/14/2026 4:47 PM, Greg Kroah-Hartman wrote:
> On Wed, Oct 14, 2026 at 04:27:11PM +0530, Prashanth K wrote:
>> Currently dwc->xhci is not cleared when xhci_plat_probe fails,
>> leading to null pointer dereference in dwc3_qcom_read_usb2_speed.
> 
> Why would that happen?  What causes it and requires it?
> 
>> Mark the xhci pointer as NULL to prevent this.
>>
>> Signed-off-by: Prashanth K <prashanth.k@oss.qualcomm.com>
> 
> What commit id does this fix?
> How was it tested?
> 
> thanks,
> 
> greg k-h

This might not fix the issue, because it doesn't take the 'err' path,
just realized that platform_device_add() doesn't return error value if
the device probe fails.

The crash happens because xhci_halt failed (not sure what caused it),
thats a functional failure from USB, but later the device crashed while
trying to perform system suspend.

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000058

Call trace:
dwc3_qcom_pm_suspend
dpm_run_callback
device_suspend
dpm_suspend
dpm_suspend_start
suspend_devices_and_enter
pm_suspend

Sorry for the spam,
Prashanth K