1, Kernel build error when ARCH=arm with multi_v7_defconfig+CONFIG_SMP=n 
	arch/arm/kernel/psci.c:287:115: error: redefinition of 'psci_init'
  This bug start from commit dbcfee724255ae1 ARM: 8457/1: psci-smp is built only for SMP
2, Kernel build error when ARCH=x86 with allmodconfig+CONFIG_OF=n or defconfig+CONFIG_KASAN=y
	include/linux/kasan.h:21:14: error: conflicting types for 'kasan_zero_pud'
	include/linux/kasan.h:20:14: error: conflicting types for 'kasan_zero_pmd'
  This bug is due to KASAN feature backporting