From: James Morse <james.morse@xxxxxxx> The kbuild robot points out that configurations without HOTPLUG_CPU selected can try to build acpi_processor_post_eject() without success as arch_unregister_cpu() is not defined. Check this explicitly. This will be merged into: | ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug for any subsequent posting. Reported-by: kbuild test robot <lkp@xxxxxxxxx> Signed-off-by: James Morse <james.morse@xxxxxxx> Tested-by: Miguel Luis <miguel.luis@xxxxxxxxxx> Tested-by: Vishnu Pajjuri <vishnu@xxxxxxxxxxxxxxxxxxxxxx> Tested-by: Jianyong Wu <jianyong.wu@xxxxxxx> --- This should probably be squashed into an earlier patch. --- drivers/acpi/acpi_processor.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index 5dabb426481f..ea12e70dfd39 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -537,7 +537,7 @@ static void acpi_processor_post_eject(struct acpi_device *device) unsigned long long sta; acpi_status status; - if (!device) + if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) || !device) return; pr = acpi_driver_data(device); -- 2.30.2