tree: https://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git master head: 34dd03a2fe9af1f1a9dbd7ec65eb1f247bdfe0db commit: 4e14c9de85753f6debbd4e6559a3036d99696326 [15/20] mm: thp: make the THP mapcount atomic against __split_huge_pmd_locked() config: arc-randconfig-r011-20210115 (attached as .config) compiler: arc-elf-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/andrea/aa.git/commit/?id=... git remote add aa https://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git git fetch --no-tags aa master git checkout 4e14c9de85753f6debbd4e6559a3036d99696326 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc 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 >>): mm/util.c: In function 'page_mapping': mm/util.c:700:15: warning: variable 'entry' set but not used [-Wunused-but-set-variable] 700 | swp_entry_t entry; | ^~~~~ mm/util.c: In function '__page_mapcount': 738 | seqcount = page_mapcount_seq_begin(page); | ^~~~~~~~~~~~~~~~~~~~~~~ | page_mapcount_reset 745 | if (page_mapcount_seq_retry(page, seqcount)) | ^~~~~~~~~~~~~~~~~~~~~~~ | page_mapcount_reset cc1: some warnings being treated as errors vim +738 mm/util.c 723 724 /* Slow path of page_mapcount() for compound pages */ 725 int __page_mapcount(struct page *page) 726 { 727 unsigned long seqcount; 728 int ret; 729 730 /* 731 * For file THP page->_mapcount contains total number of mapping 732 * of the page: no need to look into compound_mapcount. 733 */ 734 if (!PageAnon(page) && !PageHuge(page)) 735 return atomic_read(&page->_mapcount) + 1; 736 page = compound_head(page); 737 again: 739 740 ret = atomic_read(&page->_mapcount) + 1; 741 ret += atomic_read(compound_mapcount_ptr(page)) + 1; 742 if (PageDoubleMap(page)) 743 ret--; 744 746 goto again; 747 return ret; 748 } 749 EXPORT_SYMBOL_GPL(__page_mapcount); 750 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org