tree: https://github.com/hnaz/linux-mm master head: a017b085735719105714da692a82a6eeb8830718 commit: eb0f7fa78a5ced856259e759b6bad1bed2a9295c [59/194] mm: pgtable: add shortcuts for accessing kernel PMD and PTE config: powerpc-ep88xc_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 eb0f7fa78a5ced856259e759b6bad1bed2a9295c # 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 >>, old ones prefixed by <<): arch/powerpc/mm/pgtable.c: In function 'set_huge_pte_at': 267 | pmd_t *pmd = pmd_ptr(mm, addr); | ^~~~~~~ arch/powerpc/mm/pgtable.c: At top level: arch/powerpc/mm/pgtable.c:341:8: error: no previous prototype for '__find_linux_pte' [-Werror=missing-prototypes] 341 | pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea, | ^~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors vim +/pmd_ptr +267 arch/powerpc/mm/pgtable.c f159bcb25fdb31 Andrew Morton 2020-06-09 263 f159bcb25fdb31 Andrew Morton 2020-06-09 264 #if defined(CONFIG_PPC_8xx) f159bcb25fdb31 Andrew Morton 2020-06-09 265 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) f159bcb25fdb31 Andrew Morton 2020-06-09 266 { f159bcb25fdb31 Andrew Morton 2020-06-09 @267 pmd_t *pmd = pmd_ptr(mm, addr); f159bcb25fdb31 Andrew Morton 2020-06-09 268 pte_basic_t val; f159bcb25fdb31 Andrew Morton 2020-06-09 269 pte_basic_t *entry = &ptep->pte; f159bcb25fdb31 Andrew Morton 2020-06-09 270 int num = is_hugepd(*((hugepd_t *)pmd)) ? 1 : SZ_512K / SZ_4K; f159bcb25fdb31 Andrew Morton 2020-06-09 271 int i; f159bcb25fdb31 Andrew Morton 2020-06-09 272 f159bcb25fdb31 Andrew Morton 2020-06-09 273 /* f159bcb25fdb31 Andrew Morton 2020-06-09 274 * Make sure hardware valid bit is not set. We don't do f159bcb25fdb31 Andrew Morton 2020-06-09 275 * tlb flush for this update. f159bcb25fdb31 Andrew Morton 2020-06-09 276 */ f159bcb25fdb31 Andrew Morton 2020-06-09 277 VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep)); f159bcb25fdb31 Andrew Morton 2020-06-09 278 f159bcb25fdb31 Andrew Morton 2020-06-09 279 pte = pte_mkpte(pte); f159bcb25fdb31 Andrew Morton 2020-06-09 280 f159bcb25fdb31 Andrew Morton 2020-06-09 281 pte = set_pte_filter(pte); f159bcb25fdb31 Andrew Morton 2020-06-09 282 f159bcb25fdb31 Andrew Morton 2020-06-09 283 val = pte_val(pte); f159bcb25fdb31 Andrew Morton 2020-06-09 284 for (i = 0; i < num; i++, entry++, val += SZ_4K) f159bcb25fdb31 Andrew Morton 2020-06-09 285 *entry = val; f159bcb25fdb31 Andrew Morton 2020-06-09 286 } f159bcb25fdb31 Andrew Morton 2020-06-09 287 #endif f069ff396d657a Aneesh Kumar K.V 2018-05-29 288 #endif /* CONFIG_HUGETLB_PAGE */ f069ff396d657a Aneesh Kumar K.V 2018-05-29 289 :::::: The code at line 267 was first introduced by commit :::::: f159bcb25fdb31b93da0d50db40bc34e8cdcc713 origin :::::: TO: Andrew Morton <akpm(a)linux-foundation.org&gt; :::::: CC: Johannes Weiner <hannes(a)cmpxchg.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org