Hi Andrii, I love your patch! Perhaps something to improve: [auto build test WARNING on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Andrii-Nakryiko/Integrate-kernel... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: mips-randconfig-r002-20201110 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 4d81c8adb6ed9840257f6cb6b93f60856d422a15) 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 mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu # https://github.com/0day-ci/linux/commit/dcd763b7808fdc01ebf70bbe07ba92388... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Andrii-Nakryiko/Integrate-kernel-module-BTF-support/20201110-095309 git checkout dcd763b7808fdc01ebf70bbe07ba92388df4d20d # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): static struct btf char const void unsigned int data_size) ^ fatal error: error in backend: Nested variants found in inline asm string: ' .set push .set mips64r2 .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/atomic.h", .line = 154, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif 1: ll $1, $2 # atomic_fetch_sub subu $0, $1, $3 sc $0, $2 beqz $0, 1b .set pop move $0, $1 ' clang-12: error: clang frontend command failed with exit code 70 (use -v to see invocation) clang version 12.0.0 (git://gitmirror/llvm_project 874b0a0b9db93f5d3350ffe6b5efda2d908415d0) Target: mipsel-unknown-linux-gnu Thread model: posix InstalledDir: /opt/cross/clang-874b0a0b9d/bin clang-12: note: diagnostic msg: Makefile arch drivers include kernel mm scripts source usr vim +/btf_parse_module +4481 kernel/bpf/btf.c 4480 4482 { 4483 struct btf_verifier_env *env = NULL; 4484 struct bpf_verifier_log *log; 4485 struct btf *btf = NULL, *base_btf; 4486 int err; 4487 4488 base_btf = bpf_get_btf_vmlinux(); 4489 if (IS_ERR(base_btf)) 4490 return base_btf; 4491 if (!base_btf) 4492 return ERR_PTR(-EINVAL); 4493 4494 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); 4495 if (!env) 4496 return ERR_PTR(-ENOMEM); 4497 4498 log = &env->log; 4499 log->level = BPF_LOG_KERNEL; 4500 4501 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); 4502 if (!btf) { 4503 err = -ENOMEM; 4504 goto errout; 4505 } 4506 env->btf = btf; 4507 4508 btf->base_btf = base_btf; 4509 btf->start_id = base_btf->nr_types; 4510 btf->start_str_off = base_btf->hdr.str_len; 4511 btf->kernel_btf = true; 4512 snprintf(btf->name, sizeof(btf->name), "%s", module_name); 4513 4514 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN); 4515 if (!btf->data) { 4516 err = -ENOMEM; 4517 goto errout; 4518 } 4519 memcpy(btf->data, data, data_size); 4520 btf->data_size = data_size; 4521 4522 err = btf_parse_hdr(env); 4523 if (err) 4524 goto errout; 4525 4526 btf->nohdr_data = btf->data + btf->hdr.hdr_len; 4527 4528 err = btf_parse_str_sec(env); 4529 if (err) 4530 goto errout; 4531 4532 err = btf_check_all_metas(env); 4533 if (err) 4534 goto errout; 4535 4536 btf_verifier_env_free(env); 4537 refcount_set(&btf->refcnt, 1); 4538 return btf; 4539 4540 errout: 4541 btf_verifier_env_free(env); 4542 if (btf) { 4543 kvfree(btf->data); 4544 kvfree(btf->types); 4545 kfree(btf); 4546 } 4547 return ERR_PTR(err); 4548 } 4549 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org