tree: https://git.kernel.org/pub/scm/linux/kernel/git/hare/scsi-devel.git blk-namespace.v2 head: 292c56144bc8965fbf622e63bda66cc40deeac87 commit: eddd528a51cc0838c23fd1436b6d880ccc66ac45 [5/6] block: user namespace support config: m68k-allmodconfig (attached as .config) compiler: m68k-linux-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/hare/scsi-devel.git/commi... git remote add hare-scsi-devel https://git.kernel.org/pub/scm/linux/kernel/git/hare/scsi-devel.git git fetch --no-tags hare-scsi-devel blk-namespace.v2 git checkout eddd528a51cc0838c23fd1436b6d880ccc66ac45 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 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 >>): block/genhd.c: In function 'genhd_device_init': 946 | kobj_ns_type_register(&user_ns_type_operations); | ^~~~~~~~~~~~~~~~~~~~~~~ | kobj_ns_type_operations block/genhd.c:946:25: note: each undeclared identifier is reported only once for each function it appears in block/genhd.c: At top level: 1212 | .ns_type = &user_ns_type_operations, | ^~~~~~~~~~~~~~~~~~~~~~~ | kobj_ns_type_operations 1213 | .namespace = block_class_user_namespace, | ^~~~~~~~~~~~~~~~~~~~~~~~~~ 1214 | .get_ownership = block_class_get_ownership, | ^~~~~~~~~~~~~~~~~~~~~~~~~ | kobject_get_ownership vim +946 block/genhd.c 939 940 static int __init genhd_device_init(void) 941 { 942 int error; 943 944 block_class.dev_kobj = sysfs_dev_block_kobj; 945 #ifdef CONFIG_BLK_DEV_USER_NS 947 #endif 948 error = class_register(&block_class); 949 if (unlikely(error)) 950 return error; 951 blk_dev_init(); 952 953 register_blkdev(BLOCK_EXT_MAJOR, "blkext"); 954 955 /* create top-level block dir */ 956 if (!sysfs_deprecated) 957 block_depr = kobject_create_and_add("block", NULL); 958 return 0; 959 } 960 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org