tree: https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git queue-5.10 head: 9ced6633127bd25a94939777d9ecda54800859fc commit: ce4ba942d630e0361a9272fc065ee6530bc1bdd7 [56/74] mm/memcg: set memcg when splitting page config: powerpc-randconfig-r002-20210318 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 6db3ab2903f42712f44000afb5aa467efbd25f35) 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 powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git/c... git remote add sashal-linux-stable https://git.kernel.org/pub/scm/linux/kernel/git/sashal/linux-stable.git git fetch --no-tags sashal-linux-stable queue-5.10 git checkout ce4ba942d630e0361a9272fc065ee6530bc1bdd7 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang 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 >>): split_page_memcg(page, 1 << order); ^ mm/page_alloc.c:3563:15: warning: no previous prototype for function 'should_fail_alloc_page' [-Wmissing-prototypes] noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) ^ mm/page_alloc.c:3563:10: note: declare 'static' if the function is not intended to be used outside of this translation unit noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) ^ static mm/page_alloc.c:6244:23: warning: no previous prototype for function 'memmap_init' [-Wmissing-prototypes] void __meminit __weak memmap_init(unsigned long size, int nid, ^ mm/page_alloc.c:6244:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __meminit __weak memmap_init(unsigned long size, int nid, ^ static 2 warnings and 1 error generated. vim +/split_page_memcg +3275 mm/page_alloc.c 3256 3257 /* 3258 * split_page takes a non-compound higher-order page, and splits it into 3259 * n (1<<order) sub-pages: page[0..n] 3260 * Each sub-page must be freed individually. 3261 * 3262 * Note: this is probably too low level an operation for use in drivers. 3263 * Please consult with lkml before using this in your driver. 3264 */ 3265 void split_page(struct page *page, unsigned int order) 3266 { 3267 int i; 3268 3269 VM_BUG_ON_PAGE(PageCompound(page), page); 3270 VM_BUG_ON_PAGE(!page_count(page), page); 3271 3272 for (i = 1; i < (1 << order); i++) 3273 set_page_refcounted(page + i); 3274 split_page_owner(page, 1 << order); 3276 } 3277 EXPORT_SYMBOL_GPL(split_page); 3278 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org