Hi Will, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 0c947b893d69231a9add855939da7c66237ab44f commit: eb5c2d4b45e3d2d5d052ea6b8f1463976b1020d5 compiler.h: Move compiletime_assert() macros into compiler_types.h date: 1 year, 6 months ago config: mips-randconfig-r036-20220117 (https://download.01.org/0day-ci/archive/20220118/202201180323.kaEU6etu-lk...) compiler: mips-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/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout eb5c2d4b45e3d2d5d052ea6b8f1463976b1020d5 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=mips SHELL=/bin/bash arch/mips/ 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 >>): arch/mips/mm/init.c:61:6: warning: no previous prototype for 'setup_zero_pages' [-Wmissing-prototypes] 61 | void setup_zero_pages(void) | ^~~~~~~~~~~~~~~~ In file included from <command-line>: arch/mips/mm/init.c: In function 'mem_init': 338 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^ include/linux/compiler_types.h:319:25: note: in definition of macro '__compiletime_assert' 319 | prefix ## suffix(); \ | ^~~~~~ include/linux/compiler_types.h:338:9: note: in expansion of macro '_compiletime_assert' 338 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^~~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) | ^~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG' 50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) | ^~~~~~~~~~~~~~~~ arch/mips/mm/init.c:458:9: note: in expansion of macro 'BUILD_BUG_ON' 458 | BUILD_BUG_ON(IS_ENABLED(CONFIG_32BIT) && (_PFN_SHIFT > PAGE_SHIFT)); | ^~~~~~~~~~~~ vim +/__compiletime_assert_256 +338 include/linux/compiler_types.h 324 325 #define _compiletime_assert(condition, msg, prefix, suffix) \ 326 __compiletime_assert(condition, msg, prefix, suffix) 327 328 /** 329 * compiletime_assert - break build and emit msg if condition is false 330 * @condition: a compile-time constant condition to check 331 * @msg: a message to emit if condition is false 332 * 333 * In tradition of POSIX assert, this macro will break the build if the 334 * supplied condition is *false*, emitting the supplied error message if the 335 * compiler has support to do so. 336 */ 337 #define compiletime_assert(condition, msg) \ 339 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org