Hi Nylon, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 1e28eed17697bcf343c6743f0028cc3b5dd88bf0 commit: e178d670f251b6947d6be99c0014e9a57ad4f0e0 riscv/kasan: add KASAN_VMALLOC support date: 3 weeks ago config: riscv-randconfig-r022-20210315 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 7ee96429a0b057bcc97331a6a762fc3cd00aed61) 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/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 e178d670f251b6947d6be99c0014e9a57ad4f0e0 # 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 >>): void __init kasan_shallow_populate(void *start, void *end) ^ arch/riscv/mm/kasan_init.c:99:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init kasan_shallow_populate(void *start, void *end) ^ static 1 warning generated. vim +/kasan_shallow_populate +99 arch/riscv/mm/kasan_init.c 98 100 { 101 unsigned long vaddr = (unsigned long)start & PAGE_MASK; 102 unsigned long vend = PAGE_ALIGN((unsigned long)end); 103 unsigned long pfn; 104 int index; 105 void *p; 106 pud_t *pud_dir, *pud_k; 107 pgd_t *pgd_dir, *pgd_k; 108 p4d_t *p4d_dir, *p4d_k; 109 110 while (vaddr < vend) { 111 index = pgd_index(vaddr); 112 pfn = csr_read(CSR_SATP) & SATP_PPN; 113 pgd_dir = (pgd_t *)pfn_to_virt(pfn) + index; 114 pgd_k = init_mm.pgd + index; 115 pgd_dir = pgd_offset_k(vaddr); 116 set_pgd(pgd_dir, *pgd_k); 117 118 p4d_dir = p4d_offset(pgd_dir, vaddr); 119 p4d_k = p4d_offset(pgd_k, vaddr); 120 121 vaddr = (vaddr + PUD_SIZE) & PUD_MASK; 122 pud_dir = pud_offset(p4d_dir, vaddr); 123 pud_k = pud_offset(p4d_k, vaddr); 124 125 if (pud_present(*pud_dir)) { 126 p = early_alloc(PAGE_SIZE, NUMA_NO_NODE); 127 pud_populate(&init_mm, pud_dir, p); 128 } 129 vaddr += PAGE_SIZE; 130 } 131 } 132 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org