tree: https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git 20211117-sysctl-cleanups-all-set-04 head: 3559bb8939dd93c96215ab179d868c5fdc167335 commit: 99f50ec2e9ced923150fa9f7d6d9a5f767cba59c [22/36] printk: move printk sysctl to printk/sysctl.c config: microblaze-randconfig-r036-20211118 (attached as .config) compiler: microblaze-linux-gcc (GCC) 11.2.0 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/mcgrof/linux-next.git/com... git remote add mcgrof-next https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git git fetch --no-tags mcgrof-next 20211117-sysctl-cleanups-all-set-04 git checkout 99f50ec2e9ced923150fa9f7d6d9a5f767cba59c # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=microblaze If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): kernel/printk/sysctl.c:47:36: error: 'printk_delay_msec' undeclared here (not in a function) 47 | .data = &printk_delay_msec, | ^~~~~~~~~~~~~~~~~ kernel/printk/sysctl.c:59:35: error: 'devkmsg_sysctl_set_loglvl' undeclared here (not in a function) 59 | .proc_handler = devkmsg_sysctl_set_loglvl, | ^~~~~~~~~~~~~~~~~~~~~~~~~ kernel/printk/sysctl.c:63:36: error: 'dmesg_restrict' undeclared here (not in a function) 63 | .data = &dmesg_restrict, | ^~~~~~~~~~~~~~ 82 | void __init printk_sysctl_init(void) | ^~~~~~~~~~~~~~~~~~ vim +/printk_sysctl_init +82 kernel/printk/sysctl.c 81 83 { 84 register_sysctl_init("kernel", printk_sysctls, "printk"); 85 } 86 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org