Hi Oliver, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 8b12a62a4e3ed4ae99c715034f557eb391d6b196 commit: c7b74967799b1af52b3045d69d4c26836b2d41de can: replace can_dlc as variable/element for payload length date: 4 months ago config: arm-randconfig-r004-20210318 (attached as .config) compiler: arm-linux-gnueabi-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/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 c7b74967799b1af52b3045d69d4c26836b2d41de # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm 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 <command-line>: net/can/af_can.c: In function 'can_init': 315 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^ include/linux/compiler_types.h:296:4: note: in definition of macro '__compiletime_assert' 296 | prefix ## suffix(); \ | ^~~~~~ include/linux/compiler_types.h:315:2: note: in expansion of macro '_compiletime_assert' 315 | _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:50:2: note: in expansion of macro 'BUILD_BUG_ON_MSG' 50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) | ^~~~~~~~~~~~~~~~ net/can/af_can.c:891:2: note: in expansion of macro 'BUILD_BUG_ON' 891 | BUILD_BUG_ON(offsetof(struct can_frame, len) != | ^~~~~~~~~~~~ vim +/__compiletime_assert_511 +315 include/linux/compiler_types.h eb5c2d4b45e3d2 Will Deacon 2020-07-21 301 eb5c2d4b45e3d2 Will Deacon 2020-07-21 302 #define _compiletime_assert(condition, msg, prefix, suffix) \ eb5c2d4b45e3d2 Will Deacon 2020-07-21 303 __compiletime_assert(condition, msg, prefix, suffix) eb5c2d4b45e3d2 Will Deacon 2020-07-21 304 eb5c2d4b45e3d2 Will Deacon 2020-07-21 305 /** eb5c2d4b45e3d2 Will Deacon 2020-07-21 306 * compiletime_assert - break build and emit msg if condition is false eb5c2d4b45e3d2 Will Deacon 2020-07-21 307 * @condition: a compile-time constant condition to check eb5c2d4b45e3d2 Will Deacon 2020-07-21 308 * @msg: a message to emit if condition is false eb5c2d4b45e3d2 Will Deacon 2020-07-21 309 * eb5c2d4b45e3d2 Will Deacon 2020-07-21 310 * In tradition of POSIX assert, this macro will break the build if the eb5c2d4b45e3d2 Will Deacon 2020-07-21 311 * supplied condition is *false*, emitting the supplied error message if the eb5c2d4b45e3d2 Will Deacon 2020-07-21 312 * compiler has support to do so. eb5c2d4b45e3d2 Will Deacon 2020-07-21 313 */ eb5c2d4b45e3d2 Will Deacon 2020-07-21 314 #define compiletime_assert(condition, msg) \ eb5c2d4b45e3d2 Will Deacon 2020-07-21 @315 _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) eb5c2d4b45e3d2 Will Deacon 2020-07-21 316 :::::: The code at line 315 was first introduced by commit :::::: eb5c2d4b45e3d2d5d052ea6b8f1463976b1020d5 compiler.h: Move compiletime_assert() macros into compiler_types.h :::::: TO: Will Deacon <will(a)kernel.org&gt; :::::: CC: Will Deacon <will(a)kernel.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org