tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 6dd65e60af981e77a6bc142d82138c26fb18c3e9 commit: 4301edca7073d0e53c321411404bee65dfdc0324 [3897/4551] mm-fix-phys_to_target_node-and-memory_add_physaddr_to_nid-exports-v4 config: powerpc64-randconfig-r002-20201109 (attached as .config) compiler: powerpc64le-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 # 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 4301edca7073d0e53c321411404bee65dfdc0324 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc64 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 >>): 91 | int __weak create_section_mapping(unsigned long start, unsigned long end, | ^~~~~~~~~~~~~~~~~~~~~~ -- 174 | int __meminit create_section_mapping(unsigned long start, unsigned long end, | ^~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/mm/book3s64/pgtable.c:405:6: warning: no previous prototype for 'arch_report_meminfo' [-Wmissing-prototypes] 405 | void arch_report_meminfo(struct seq_file *m) | ^~~~~~~~~~~~~~~~~~~ arch/powerpc/mm/book3s64/pgtable.c:461:5: warning: no previous prototype for 'pmd_move_must_withdraw' [-Wmissing-prototypes] 461 | int pmd_move_must_withdraw(struct spinlock *new_pmd_ptl, | ^~~~~~~~~~~~~~~~~~~~~~ vim +/create_section_mapping +91 arch/powerpc/mm/mem.c bc02af93dd2bbdd Yasunori Goto 2006-06-27 90 4e00c5affdd4b04 Logan Gunthorpe 2020-04-10 @91 int __weak create_section_mapping(unsigned long start, unsigned long end, 4e00c5affdd4b04 Logan Gunthorpe 2020-04-10 92 int nid, pgprot_t prot) fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05 93 { fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05 94 return -ENODEV; fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05 95 } fecbfabe1dc9405 Benjamin Herrenschmidt 2016-07-05 96 :::::: The code at line 91 was first introduced by commit :::::: 4e00c5affdd4b04e6392001716333971932f3d0c powerpc/mm: thread pgprot_t through create_section_mapping() :::::: TO: Logan Gunthorpe <logang(a)deltatee.com&gt; :::::: CC: Linus Torvalds <torvalds(a)linux-foundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org