tree: https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git asm-generic-uaccess-5 head: a8cdb21b715276b7638a636237489f2425c24180 commit: 3a68cb1dbf65aa5c86ae185e5c51c5c26c31a54a [1/8] asm-generic/uaccess.h: remove __strncpy_from_user/__strnlen_user config: um-x86_64_defconfig (attached as .config) compiler: gcc-10 (Ubuntu 10.3.0-1ubuntu1~20.04) 10.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git/comm... git remote add asm-generic https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git git fetch --no-tags asm-generic asm-generic-uaccess-5 git checkout 3a68cb1dbf65aa5c86ae185e5c51c5c26c31a54a # save the attached .config to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash 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 >>): In file included from arch/um/include/asm/uaccess.h:39, from include/linux/uaccess.h:11, from include/linux/sched/task.h:11, from include/linux/sched/signal.h:9, from include/linux/rcuwait.h:6, from include/linux/percpu-rwsem.h:7, from include/linux/fs.h:33, from include/linux/highmem.h:5, from arch/um/kernel/skas/uaccess.c:7: arch/um/kernel/skas/uaccess.c: In function 'strnlen_user': 246 | if (!access_ok(src, 1)) | ^~~ include/asm-generic/uaccess.h:124:59: note: in definition of macro 'access_ok' 124 | #define access_ok(addr, size) __access_ok((unsigned long)(addr),(size)) | ^~~~ arch/um/kernel/skas/uaccess.c:246:17: note: each undeclared identifier is reported only once for each function it appears in 246 | if (!access_ok(src, 1)) | ^~~ include/asm-generic/uaccess.h:124:59: note: in definition of macro 'access_ok' 124 | #define access_ok(addr, size) __access_ok((unsigned long)(addr),(size)) | ^~~~ vim +/src +246 arch/um/kernel/skas/uaccess.c 241 242 long strnlen_user(const void __user *str, long len) 243 { 244 int count = 0, n; 245 247 return -EFAULT; 248 249 if (uaccess_kernel()) 250 return strnlen((__force char*)str, len) + 1; 251 252 n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count); 253 if (n == 0) 254 return count + 1; 255 return 0; 256 } 257 EXPORT_SYMBOL(strnlen_user); 258 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org