Hi Lorenzo, Thank you for the patch! Yet something to improve: [auto build test ERROR on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Bianconi/net-netfilter-add-kfunc-helper-to-update-ct-timeout/20220527-053913 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: x86_64-randconfig-a005 (https://download.01.org/0day-ci/archive/20220527/202205271522.W0HxUVz1-lkp@xxxxxxxxx/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 134d7f9a4b97e9035150d970bd9e376043c4577e) 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://github.com/intel-lab-lkp/linux/commit/c346565af9b023d9231ca8fca2e1b8c66a782f84 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Lorenzo-Bianconi/net-netfilter-add-kfunc-helper-to-update-ct-timeout/20220527-053913 git checkout c346565af9b023d9231ca8fca2e1b8c66a782f84 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash net/ If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): >> net/core/filter.c:10479:9: error: call to undeclared function 'btf_struct_access'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, flag); ^ 1 error generated. vim +/btf_struct_access +10479 net/core/filter.c 10459 10460 static int xdp_tc_btf_struct_access(struct bpf_verifier_log *log, 10461 const struct btf *btf, 10462 const struct btf_type *t, int off, int size, 10463 enum bpf_access_type atype, 10464 u32 *next_btf_id, enum bpf_type_flag *flag) 10465 { 10466 int ret; 10467 10468 if (atype == BPF_READ || !READ_ONCE(nf_conn_btf_struct_access)) 10469 goto end; 10470 mutex_lock(&nf_conn_btf_struct_access_mtx); 10471 if (!nf_conn_btf_struct_access) 10472 goto end_unlock; 10473 ret = nf_conn_btf_struct_access(log, btf, t, off, size, atype, next_btf_id, flag); 10474 mutex_unlock(&nf_conn_btf_struct_access_mtx); 10475 return ret; 10476 end_unlock: 10477 mutex_unlock(&nf_conn_btf_struct_access_mtx); 10478 end: 10479 return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, flag); 10480 } 10481 -- 0-DAY CI Kernel Test Service https://01.org/lkp