tree: https://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc.git arm64-vdso head: 6b510319fdb2cc4136a47319f6c5e88195b4bcf0 commit: fdf2f42836c8f11889209ddd41450f6d7d0944e3 [4/5] arm64: vdso: Add getcpu() implementation config: arm64-randconfig-r006-20200819 (attached as .config) compiler: aarch64-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout fdf2f42836c8f11889209ddd41450f6d7d0944e3 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): 33 | int __kernel_getcpu(unsigned int *cpu, unsigned int *node, | ^~~~~~~~~~~~~~~ -- arch/arm64/kernel/vdso/vgettimeofday.c:9:5: warning: no previous prototype for '__kernel_clock_gettime' [-Wmissing-prototypes] 9 | int __kernel_clock_gettime(clockid_t clock, | ^~~~~~~~~~~~~~~~~~~~~~ arch/arm64/kernel/vdso/vgettimeofday.c:15:5: warning: no previous prototype for '__kernel_gettimeofday' [-Wmissing-prototypes] 15 | int __kernel_gettimeofday(struct __kernel_old_timeval *tv, | ^~~~~~~~~~~~~~~~~~~~~ arch/arm64/kernel/vdso/vgettimeofday.c:21:5: warning: no previous prototype for '__kernel_clock_getres' [-Wmissing-prototypes] 21 | int __kernel_clock_getres(clockid_t clock_id, | ^~~~~~~~~~~~~~~~~~~~~ 33 | int __kernel_getcpu(unsigned int *cpu, unsigned int *node, | ^~~~~~~~~~~~~~~ # https://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc.git/commit/?... git remote add broonie-misc https://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc.git git fetch --no-tags broonie-misc arm64-vdso git checkout fdf2f42836c8f11889209ddd41450f6d7d0944e3 vim +/__kernel_getcpu +33 arch/arm64/kernel/vdso/vgetcpu.c 32 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org