Kernel test robot reports build breakage with commit 5f5e49e999ac ("ACPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()") when !CONFIG_HOTPLUG_CPU/!CONFIG_SMP. wakeup_cpu0() is defined under CONFIG_SMP and start_cpu0() under CONFIG_HOTPLUG_CPU which, in its turn, depend on CONFIG_SMP. Add #ifdef CONFIG_HOTPLUG_CPU to the block, this should be sufficient. Reported-by: kernel test robot <lkp@xxxxxxxxx> Fixes: 5f5e49e999ac ("ACPI: processor: Fix CPU0 wakeup in acpi_idle_play_dead()") Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> --- drivers/acpi/processor_idle.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index f0c73f658880..0925b1477230 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -539,7 +539,7 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index) } else return -ENODEV; -#ifdef CONFIG_X86 +#if defined(CONFIG_X86) && defined(CONFIG_HOTPLUG_CPU) /* If NMI wants to wake up CPU0, start CPU0. */ if (wakeup_cpu0()) start_cpu0(); -- 2.30.2