tree: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git kspp/memcpy/next-20210519/v0 head: 48fff7f29af65f2ab9e56bc71a0ef652f91a68cd commit: 0bee95cae61e3cfc979fb3baab53189b65f5f777 [52/53] [DEBUG] fortify: Warn about all cases where memcpy() cannot check bounds config: s390-allyesconfig (attached as .config) compiler: s390-linux-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/kees/linux.git/commit/?id... git remote add kees https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git git fetch --no-tags kees kspp/memcpy/next-20210519/v0 git checkout 0bee95cae61e3cfc979fb3baab53189b65f5f777 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Note: the kees/kspp/memcpy/next-20210519/v0 HEAD 48fff7f29af65f2ab9e56bc71a0ef652f91a68cd builds fine. It only hurts bisectibility. All errors (new ones prefixed by >>): In file included from include/linux/string.h:260, from include/linux/uuid.h:12, from include/linux/mod_devicetable.h:13, from scripts/mod/devicetable-offsets.c:3: include/linux/fortify-string.h: In function '__fortify_memcpy_chk': 259 | __runtime_write_check_missing(); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | __runtime_write_check 261 | __runtime_read_check_missing(); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ | __runtime_read_check cc1: some warnings being treated as errors make[2]: *** [scripts/Makefile.build:118: scripts/mod/devicetable-offsets.s] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1307: prepare0] Error 2 make[1]: Target 'modules_prepare' not remade because of errors. make: *** [Makefile:222: __sub-make] Error 2 make: Target 'modules_prepare' not remade because of errors. -- scripts/genksyms/parse.y: warning: 9 shift/reduce conflicts [-Wconflicts-sr] scripts/genksyms/parse.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr] In file included from include/linux/string.h:260, from include/linux/uuid.h:12, from include/linux/mod_devicetable.h:13, from scripts/mod/devicetable-offsets.c:3: include/linux/fortify-string.h: In function '__fortify_memcpy_chk': 259 | __runtime_write_check_missing(); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | __runtime_write_check 261 | __runtime_read_check_missing(); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ | __runtime_read_check cc1: some warnings being treated as errors make[2]: *** [scripts/Makefile.build:118: scripts/mod/devicetable-offsets.s] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1307: prepare0] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:222: __sub-make] Error 2 make: Target 'prepare' not remade because of errors. vim +259 include/linux/fortify-string.h 181 182 /* 183 * To make sure the compiler can enforce protection against buffer overflows, 184 * memcpy() must not be used beyond individual array fields. If you need to 185 * copy across multiple array fields, please use struct_group() to create a 186 * named mirror of an anonymous struct union. (e.g. see struct sk_buff.) 187 * 188 * Mitigation coverage 189 * Bounds checking at: 190 * +-------+-------+-------+-------+ 191 * | Compile time | Run time | 192 * memcpy() argument sizes: | write | read | write | read | 193 * +-------+-------+-------+-------+ 194 * memcpy(known, known, constant) | y | y | n/a | n/a | 195 * memcpy(unknown, known, constant) | n | y | W | n/a | 196 * memcpy(known, unknown, constant) | y | n | n/a | W | 197 * memcpy(unknown, unknown, constant) | n | n | W | W | 198 * memcpy(known, known, dynamic) | n | n | B | B | 199 * memcpy(unknown, known, dynamic) | n | n | W | B | 200 * memcpy(known, unknown, dynamic) | n | n | B | W | 201 * memcpy(unknown, unknown, dynamic) | n | n | W | W | 202 * +-------+-------+-------+-------+ 203 * 204 * y = deterministic compile-time bounds checking 205 * n = cannot do deterministic compile-time bounds checking 206 * n/a = no run-time bounds checking needed since compile-time deterministic 207 * W = compile-time warn about lack of any bounds checking 208 * B = perform run-time bounds checking 209 * 210 */ 211 __FORTIFY_INLINE void __fortify_memcpy_chk(void *p, const void *q, 212 __kernel_size_t size, 213 const char *func) 214 { 215 size_t p_size = __builtin_object_size(p, 0); 216 size_t q_size = __builtin_object_size(q, 0); 217 size_t p_size_field = __builtin_object_size(p, 1); 218 size_t q_size_field = __builtin_object_size(q, 1); 219 220 if (__builtin_constant_p(size)) { 221 /* 222 * Length argument is a constant expression, so we 223 * can perform compile-time bounds checking where 224 * buffer sizes are known. 225 */ 226 227 /* 228 * Call attention to 0-sized targets, which indicate 229 * 0-length target names like used by sk_buff. 230 */ 231 if (!p_size_field && size > 0) 232 __write_zero(); 233 if (!q_size_field && size > 0) 234 __read_zero(); 235 236 /* Disallow size argument larger than dest/src field. */ 237 if (p_size_field < size) 238 __write_overflow_field(); 239 if (q_size_field < size) 240 __read_overflow2_field(); 241 } else { 242 /* 243 * Length argument is not a constant expression, so 244 * run-time bounds checking can happen where buffer 245 * sizes are known. 246 */ 247 248 /* Add build warnings to identify new run-time checks. */ 249 if (p_size != p_size_field) 250 __runtime_write_check(); 251 if (q_size != q_size_field) 252 __runtime_read_check(); 253 254 /* 255 * Add build warnings to identify cases where it is 256 * not possible to perform run-time bounds checks. 257 */ 258 if (p_size == (size_t)(-1)) 260 if (q_size == (size_t)(-1)) 262 263 /* Warn when writing beyond destination field size. */ 264 WARN_ON(p_size != p_size_field && p_size_field < size); 265 /* Warn when reading beyond source field size. */ 266 WARN_ON(q_size != q_size_field && q_size_field < size); 267 268 /* 269 * Always stop accesses beyond the struct that contains the 270 * field, when the buffer's remaining size is known. 271 */ 272 if ((p_size != (size_t)(-1) && p_size < size) || 273 (q_size != (size_t)(-1) && q_size < size)) 274 fortify_panic(func); 275 } 276 } 277 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org