cc1: all warnings being treated as errors kernel/cpu.c:1061:25: warning: the comparison will always evaluate as ‘true’ for the address of ‘frozen_cpus’ will never be NULL [-Waddress] kernel/extable.c:44:59: warning: comparison between two arrays [-Warray-compare] kernel/sched/core.c:7926:30: warning: the comparison will always evaluate as ‘false’ for the address of ‘cpu_isolated_map’ will never be NULL [-Waddress]