[kbuild-all] [linux-next:master 5868/6773] arch/powerpc/mm/mem.c:91:12: warning: no previous prototype for function 'create_section_mapping'

tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 2052923327794192c5d884623b5ee5fec1867bda commit: d106ad47e292fde47fc09e16a2ddc13609ff2ad1 [5868/6773] mm-fix-phys_to_target_node-and-memory_add_physaddr_to_nid-exports-v4 config: powerpc64-randconfig-r026-20201118 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b2613fb2f0f53691dd0211895afbb9413457fca7) 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 powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-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 d106ad47e292fde47fc09e16a2ddc13609ff2ad1 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang 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 >>): int __weak create_section_mapping(unsigned long start, unsigned long end, ^ arch/powerpc/mm/mem.c:91:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int __weak create_section_mapping(unsigned long start, unsigned long end, ^ static 1 warning generated. 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