Hi Nathan, I love your patch! Perhaps something to improve: [auto build test WARNING on 7c53f6b671f4aba70ff15e1b05148b10d58c2837] url: https://github.com/0day-ci/linux/commits/Nathan-Chancellor/ubsan-Implement-__ubsan_handle_alignment_assumption/20210113-055714 base: 7c53f6b671f4aba70ff15e1b05148b10d58c2837 config: arm64-randconfig-r031-20210112 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 32bcfcda4e28375e5a85268d2acfabcfcc011abf) 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 # install arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://github.com/0day-ci/linux/commit/775adad26a60878926c0ee6cd460a1375bbe51e6 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Nathan-Chancellor/ubsan-Implement-__ubsan_handle_alignment_assumption/20210113-055714 git checkout 775adad26a60878926c0ee6cd460a1375bbe51e6 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): lib/ubsan.c:192:6: warning: no previous prototype for function '__ubsan_handle_add_overflow' [-Wmissing-prototypes] void __ubsan_handle_add_overflow(void *data, ^ lib/ubsan.c:192:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_add_overflow(void *data, ^ static lib/ubsan.c:200:6: warning: no previous prototype for function '__ubsan_handle_sub_overflow' [-Wmissing-prototypes] void __ubsan_handle_sub_overflow(void *data, ^ lib/ubsan.c:200:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_sub_overflow(void *data, ^ static lib/ubsan.c:207:6: warning: no previous prototype for function '__ubsan_handle_mul_overflow' [-Wmissing-prototypes] void __ubsan_handle_mul_overflow(void *data, ^ lib/ubsan.c:207:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_mul_overflow(void *data, ^ static lib/ubsan.c:214:6: warning: no previous prototype for function '__ubsan_handle_negate_overflow' [-Wmissing-prototypes] void __ubsan_handle_negate_overflow(void *_data, void *old_val) ^ lib/ubsan.c:214:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_negate_overflow(void *_data, void *old_val) ^ static lib/ubsan.c:234:6: warning: no previous prototype for function '__ubsan_handle_divrem_overflow' [-Wmissing-prototypes] void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs) ^ lib/ubsan.c:234:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs) ^ static lib/ubsan.c:315:6: warning: no previous prototype for function '__ubsan_handle_type_mismatch' [-Wmissing-prototypes] void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, ^ lib/ubsan.c:315:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, ^ static lib/ubsan.c:329:6: warning: no previous prototype for function '__ubsan_handle_type_mismatch_v1' [-Wmissing-prototypes] void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr) ^ lib/ubsan.c:329:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr) ^ static lib/ubsan.c:343:6: warning: no previous prototype for function '__ubsan_handle_out_of_bounds' [-Wmissing-prototypes] void __ubsan_handle_out_of_bounds(void *_data, void *index) ^ lib/ubsan.c:343:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_out_of_bounds(void *_data, void *index) ^ static lib/ubsan.c:360:6: warning: no previous prototype for function '__ubsan_handle_shift_out_of_bounds' [-Wmissing-prototypes] void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs) ^ lib/ubsan.c:360:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs) ^ static lib/ubsan.c:402:6: warning: no previous prototype for function '__ubsan_handle_builtin_unreachable' [-Wmissing-prototypes] void __ubsan_handle_builtin_unreachable(void *_data) ^ lib/ubsan.c:402:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_builtin_unreachable(void *_data) ^ static lib/ubsan.c:412:6: warning: no previous prototype for function '__ubsan_handle_load_invalid_value' [-Wmissing-prototypes] void __ubsan_handle_load_invalid_value(void *_data, void *val) ^ lib/ubsan.c:412:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_load_invalid_value(void *_data, void *val) ^ static >> lib/ubsan.c:431:6: warning: no previous prototype for function '__ubsan_handle_alignment_assumption' [-Wmissing-prototypes] void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, ^ lib/ubsan.c:431:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, ^ static 12 warnings generated. vim +/__ubsan_handle_alignment_assumption +431 lib/ubsan.c 411 > 412 void __ubsan_handle_load_invalid_value(void *_data, void *val) 413 { 414 struct invalid_value_data *data = _data; 415 char val_str[VALUE_LENGTH]; 416 417 if (suppress_report(&data->location)) 418 return; 419 420 ubsan_prologue(&data->location, "invalid-load"); 421 422 val_to_string(val_str, sizeof(val_str), data->type, val); 423 424 pr_err("load of value %s is not a valid value for type %s\n", 425 val_str, data->type->type_name); 426 427 ubsan_epilogue(); 428 } 429 EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); 430 > 431 void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org