tree: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-5.15/block head: 99d26de2f6d79badc80f55b54bd90d4cb9d1ad90 commit: 5ed964f8e54eb3191b8b7b45aeb52672a0c995dc [48/54] mm: hide laptop_mode_wb_timer entirely behind the BDI API config: sh-randconfig-r034-20210810 (attached as .config) compiler: sh4-linux-gcc (GCC) 10.3.0 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/axboe/linux-block.git/com... git remote add block https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git git fetch --no-tags block for-5.15/block git checkout 5ed964f8e54eb3191b8b7b45aeb52672a0c995dc # save the attached .config to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross O=build_dir ARCH=sh SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Note: the block/for-5.15/block HEAD 99d26de2f6d79badc80f55b54bd90d4cb9d1ad90 builds fine. It only hurts bisectibility. All errors (new ones prefixed by >>): In file included from include/linux/workqueue.h:9, from include/linux/mm_types.h:16, from include/linux/mmzone.h:21, from include/linux/gfp.h:6, from include/linux/xarray.h:14, from include/linux/radix-tree.h:19, from include/linux/fs.h:15, from include/linux/backing-dev.h:13, from mm/backing-dev.c:5: mm/backing-dev.c: In function 'bdi_alloc': 810 | timer_setup(&bdi->laptop_mode_wb_timer, laptop_mode_timer_fn, 0); | ^~~~~~~~~~~~~~~~~~~~ include/linux/timer.h:115:29: note: in definition of macro '__init_timer' 115 | init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\ | ^~~ mm/backing-dev.c:810:2: note: in expansion of macro 'timer_setup' 810 | timer_setup(&bdi->laptop_mode_wb_timer, laptop_mode_timer_fn, 0); | ^~~~~~~~~~~ mm/backing-dev.c:810:42: note: each undeclared identifier is reported only once for each function it appears in 810 | timer_setup(&bdi->laptop_mode_wb_timer, laptop_mode_timer_fn, 0); | ^~~~~~~~~~~~~~~~~~~~ include/linux/timer.h:115:29: note: in definition of macro '__init_timer' 115 | init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\ | ^~~ mm/backing-dev.c:810:2: note: in expansion of macro 'timer_setup' 810 | timer_setup(&bdi->laptop_mode_wb_timer, laptop_mode_timer_fn, 0); | ^~~~~~~~~~~ vim +/laptop_mode_timer_fn +810 mm/backing-dev.c 794 795 struct backing_dev_info *bdi_alloc(int node_id) 796 { 797 struct backing_dev_info *bdi; 798 799 bdi = kzalloc_node(sizeof(*bdi), GFP_KERNEL, node_id); 800 if (!bdi) 801 return NULL; 802 803 if (bdi_init(bdi)) { 804 kfree(bdi); 805 return NULL; 806 } 807 bdi->capabilities = BDI_CAP_WRITEBACK | BDI_CAP_WRITEBACK_ACCT; 808 bdi->ra_pages = VM_READAHEAD_PAGES; 809 bdi->io_pages = VM_READAHEAD_PAGES; 811 return bdi; 812 } 813 EXPORT_SYMBOL(bdi_alloc); 814 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org