Hi Tong, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: c7d4c1fd91ab4a6d2620497921a9c6bf54650ab8 commit: 7b9dbbb41e1e6579d21fbec1d85ed04a392f73e9 [8714/10489] riscv: add VMAP_STACK overflow detection config: riscv-randconfig-r021-20210617 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 64720f57bea6a6bf033feef4a5751ab9c0c3b401) 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 # install riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 7b9dbbb41e1e6579d21fbec1d85ed04a392f73e9 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv 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 >>): asmlinkage unsigned long get_overflow_stack(void) ^ arch/riscv/kernel/traps.c:210:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage unsigned long get_overflow_stack(void) ^ static asmlinkage void handle_bad_stack(struct pt_regs *regs) ^ arch/riscv/kernel/traps.c:216:12: note: declare 'static' if the function is not intended to be used outside of this translation unit asmlinkage void handle_bad_stack(struct pt_regs *regs) ^ static 2 warnings generated. Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for LOCKDEP Depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) Selected by - DEBUG_LOCK_ALLOC && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT vim +/get_overflow_stack +210 arch/riscv/kernel/traps.c 201 202 #ifdef CONFIG_VMAP_STACK 203 DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack) 204 __aligned(16); 205 /* 206 * shadow stack, handled_ kernel_ stack_ overflow(in kernel/entry.S) is used 207 * to get per-cpu overflow stack(get_overflow_stack). 208 */ 209 long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE/sizeof(long)]; 211 { 212 return (unsigned long)this_cpu_ptr(overflow_stack) + 213 OVERFLOW_STACK_SIZE; 214 } 215 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org