Hi WingMan, FYI, the error/warning still remains. tree: git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git ti-rt-linux-5.10.y head: ac3657d2050406e974383b1490184f42a06b73cc commit: e355bf097bb11257afeadf6665e51f224eeb93a7 [6649/6833] net: packet: Pass on redundant net info in packet_recvmsg config: parisc-randconfig-r022-20210817 (attached as .config) compiler: hppa-linux-gcc (GCC) 11.2.0 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 git remote add ti git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git git fetch --no-tags ti ti-rt-linux-5.10.y git checkout e355bf097bb11257afeadf6665e51f224eeb93a7 # save the attached .config to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=parisc SHELL=/bin/bash kernel/cgroup/ 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 >>): In file included from kernel/cgroup/cgroup.c:60: include/net/sock.h: In function 'sock_recv_redundant_info': 2523 | put_cmsg(msg, SOL_SOCKET, SCM_REDUNDANT, sizeof(*sred), sred); | ^~~~~~~~~~~~~ include/net/sock.h:2523:43: note: each undeclared identifier is reported only once for each function it appears in vim +/SCM_REDUNDANT +2523 include/net/sock.h 2514 2515 DECLARE_STATIC_KEY_FALSE(tcp_rx_skb_cache_key); 2516 static inline void sock_recv_redundant_info(struct msghdr *msg, struct sock *sk, 2517 struct sk_buff *skb) 2518 { 2519 struct skb_redundant_info *sred; 2520 2521 sred = skb_redinfo(skb); 2522 if (sred->lsdu_size) 2524 } 2525 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org