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@xxxxxxxxxxxxxxxx>
> 
> 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