Hi Florian, I love your patch! Yet something to improve: [auto build test ERROR on mptcp/export] [cannot apply to linus/master v5.17-rc4 next-20220217] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Florian-Westphal/mptcp-replace-p... base: https://github.com/multipath-tcp/mptcp_net-next.git export config: mips-buildonly-randconfig-r002-20220217 (https://download.01.org/0day-ci/archive/20220218/202202180141.VfybVriM-lk...) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e) 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/044982520ba41e284eebe48421fad7feb... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Florian-Westphal/mptcp-replace-per-addr-listener-sockets/20220217-222844 git checkout 044982520ba41e284eebe48421fad7feb55f2106 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash net/mptcp/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): lsk = pernet->join6.sk; ^~~~~ join4 net/mptcp/ctrl.c:49:23: note: 'join4' declared here struct mptcp_join_sk join4; ^ 1 error generated. vim +251 net/mptcp/ctrl.c 205 206 struct sock *__mptcp_handle_join(int af, struct sk_buff *skb) 207 { 208 struct mptcp_options_received mp_opt; 209 struct mptcp_pernet *pernet; 210 struct socket *ssock; 211 struct sock *lsk; 212 struct net *net; 213 214 /* paranoia check: don't allow 0 destination port, 215 * else __inet_inherit_port will insert the child socket 216 * into the phony hash slot of the pernet listener. 217 */ 218 if (tcp_hdr(skb)->dest == 0) 219 return NULL; 220 221 mptcp_get_options(skb, &mp_opt); 222 223 if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ)) 224 return NULL; 225 226 net = dev_net(skb_dst(skb)->dev); 227 if (!mptcp_is_enabled(net)) 228 return NULL; 229 230 /* RFC8684: If the token is unknown [..], the receiver will send 231 * back a reset (RST) signal, analogous to an unknown port in TCP, 232 * containing an MP_TCPRST option (Section 3.6) [..] 233 */ 234 if (!mptcp_token_exists(net, mp_opt.token)) { 235 struct mptcp_ext *ext = skb_ext_add(skb, SKB_EXT_MPTCP); 236 237 if (ext) { 238 memset(ext, 0, sizeof(*ext)); 239 ext->reset_reason = MPTCP_RST_EMPTCP; 240 } 241 return NULL; 242 } 243 244 pernet = mptcp_get_pernet(net); 245 246 switch (af) { 247 case AF_INET: 248 lsk = pernet->join4.sk; 249 break; 250 case AF_INET6: 252 break; 253 default: 254 WARN_ON_ONCE(1); 255 return NULL; 256 } 257 258 ssock = __mptcp_nmpc_socket(mptcp_sk(lsk)); 259 if (WARN_ON(!ssock)) 260 return NULL; 261 262 return ssock->sk; 263 } 264 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org