Hi Rong, kernel test robot noticed the following build errors:
[auto build test ERROR on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Rong-Tao/selftests-bpf-Test-bpf_strcat-bpf_strncat-kfuncs/20260807-065842 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master patch link: https://lore.kernel.org/r/tencent_DB0510330C3A8574B3C62E6154165FCB4709%40qq.com patch subject: [PATCH bpf-next v2 2/2] selftests/bpf: Test bpf_strcat,bpf_strncat kfuncs config: s390-randconfig-r052-20260807 (https://download.01.org/0day-ci/archive/20260808/[email protected]/config) compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 12df34b8469b8095359de8c249cb1b2753fadeea) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260808/[email protected]/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <[email protected]> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ All errors (new ones prefixed by >>): >> kernel/bpf/helpers.c:4228:3: error: invalid lvalue in asm output 4228 | __put_kernel_nofault(dst + dlen + copied, &cs, char, err_out); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/uaccess.h:612:2: note: expanded from macro '__put_kernel_nofault' 612 | arch_put_kernel_nofault(dst, src, type, local_label); \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/s390/include/asm/uaccess.h:471:33: note: expanded from macro 'arch_put_kernel_nofault' 471 | #define arch_put_kernel_nofault __mvc_kernel_nofault | ^ arch/s390/include/asm/uaccess.h:424:19: note: expanded from macro '__mvc_kernel_nofault' 424 | : [_dst] "=Q" (*(type *)dst) \ | ^~~~~~~~~~~~ kernel/bpf/helpers.c:4233:2: error: invalid lvalue in asm output 4233 | __put_kernel_nofault(dst + dlen + copied, &cs, char, err_out); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/uaccess.h:612:2: note: expanded from macro '__put_kernel_nofault' 612 | arch_put_kernel_nofault(dst, src, type, local_label); \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/s390/include/asm/uaccess.h:471:33: note: expanded from macro 'arch_put_kernel_nofault' 471 | #define arch_put_kernel_nofault __mvc_kernel_nofault | ^ arch/s390/include/asm/uaccess.h:424:19: note: expanded from macro '__mvc_kernel_nofault' 424 | : [_dst] "=Q" (*(type *)dst) \ | ^~~~~~~~~~~~ 2 errors generated. vim +4228 kernel/bpf/helpers.c 4197 4198 static int __bpf_strncat(char *dst, u32 dsz, const char *src, u32 sz) 4199 { 4200 int dlen, slen, space, copied; 4201 char cs = '?'; 4202 4203 if (!copy_from_kernel_nofault_allowed(dst, 1) || 4204 !copy_from_kernel_nofault_allowed(src, 1)) { 4205 return -ERANGE; 4206 } 4207 4208 dlen = bpf_strnlen(dst, dsz); 4209 if (dlen < 0) 4210 return dlen; 4211 slen = bpf_strnlen(src, sz); 4212 if (slen < 0) 4213 return slen; 4214 4215 if (dlen >= dsz || sz == 0 || dsz == 0) 4216 return -EINVAL; 4217 4218 space = dsz - dlen; 4219 if (space <= 1 || space < min(slen, sz) + 1) 4220 return -E2BIG; 4221 4222 guard(pagefault)(); 4223 for (copied = 0; copied < space - 1 && copied < slen; copied++) { 4224 __get_kernel_nofault(&cs, src, char, err_out); 4225 if (cs == '\0') 4226 break; 4227 > 4228 __put_kernel_nofault(dst + dlen + copied, &cs, char, > err_out); 4229 4230 src++; 4231 } 4232 cs = '\0'; 4233 __put_kernel_nofault(dst + dlen + copied, &cs, char, err_out); 4234 4235 __get_kernel_nofault(&cs, src, char, err_out); 4236 if (cs != '\0' && sz > copied) 4237 return -E2BIG; 4238 4239 return dlen + copied; 4240 err_out: 4241 return -EFAULT; 4242 } 4243 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
