Hello, On 11.02.21 17:51, kernel test robot wrote: This hash references to the commit ("can: replace can_dlc as variable/element for payload length") which makes a change to the BUILD_BUG_ON() content but this does not cause the root problem. Going back some commits shows the commit ("can: add optional DLC element to Classical CAN frame structure") with hash https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... is introducing the reported problem. I assume BUILD_BUG_ON() does not work with the newly introduced union{} in struct can_frame in this specific (arm) architecture. There are no compile issues like this on x86. When removing the union{} from the struct can_frame and replacing it just with 'len' in the reported c7b74967799b1 commit, it compiles without problems. Regards, Oliver > 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': >>> include/linux/compiler_types.h:315:38: error: call to '__compiletime_assert_498' declared with attribute error: BUILD_BUG_ON failed: offsetof(struct can_frame, len) != offsetof(struct canfd_frame, len) || offsetof(struct can_frame, data) != offsetof(struct canfd_frame, data) > 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_498 +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 >