tree: https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git report-refcounts head: 6784319c4da4ff33090c0679fec1f93fe3822852 commit: 6784319c4da4ff33090c0679fec1f93fe3822852 [363/363] xfs: export reference count information to userspace config: x86_64-randconfig-a006-20210826 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/commit/?id=6784319c4da4ff33090c0679fec1f93fe3822852 git remote add djwong-xfs https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git git fetch --no-tags djwong-xfs report-refcounts git checkout 6784319c4da4ff33090c0679fec1f93fe3822852 # save the attached .config to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): In file included from :32: >> ./usr/include/linux/fsrefcounts.h:68:19: error: unknown type name 'size_t' 68 | static __inline__ size_t | ^~~~~~ --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org