[kbuild-all] arch/powerpc/kernel/traps.c:1640:6: error: no previous prototype for 'stack_overflow_exception'

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 581cb3a26baf846ee9636214afaa5333919875b1 commit: 3978eb78517c1fc06dd75405d732af45c80f5bd2 powerpc/32: Add early stack overflow detection with VMAP stack. date: 8 months ago config: powerpc-mpc8272_ads_defconfig (attached as .config) compiler: powerpc-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 3978eb78517c1fc06dd75405d732af45c80f5bd2 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): 1640 | void stack_overflow_exception(struct pt_regs *regs) | ^~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 3978eb78517c1fc06dd75405d732af45c80f5bd2 vim +/stack_overflow_exception +1640 arch/powerpc/kernel/traps.c 1639 1641 { 1642 enum ctx_state prev_state = exception_enter(); 1643 1644 die("Kernel stack overflow", regs, SIGSEGV); 1645 1646 exception_exit(prev_state); 1647 } 1648 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org