Hi Grygorii, First bad commit (maybe != root cause): tree: git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git ti-linux-5.4.y head: c02b2da68c63deb35dc5a7c1b0bbc68e4ee38632 commit: 93fac9fa368d4c49b62745b6f324d019fb42ecc4 [9521/12984] HACK: scripts: headers_install: fix allmodconfig builds config: mips-randconfig-r011-20210113 (attached as .config) compiler: mipsel-linux-gcc (GCC) 9.3.0 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-linux-5.4.y git checkout 93fac9fa368d4c49b62745b6f324d019fb42ecc4 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 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 errors (new ones prefixed by >>): In file included from include/net/cls_cgroup.h:14, from net/socket.c:95: include/net/sock.h: In function 'sock_recv_redundant_info': include/net/sock.h:2461:29: error: 'SCM_REDUNDANT' undeclared (first use in this function) 2461 | put_cmsg(msg, SOL_SOCKET, SCM_REDUNDANT, sizeof(*sred), sred); | ^~~~~~~~~~~~~ include/net/sock.h:2461:29: note: each undeclared identifier is reported only once for each function it appears in net/socket.c: In function '__sock_recv_redinfo_timestamp': 847 | SCM_RED_TIMESTAMPING, sizeof(tss), &tss); | ^~~~~~~~~~~~~~~~~~~~ net/socket.c: In function '__sys_getsockopt': net/socket.c:2132:6: warning: variable 'max_optlen' set but not used [-Wunused-but-set-variable] 2132 | int max_optlen; | ^~~~~~~~~~ vim +/SCM_RED_TIMESTAMPING +847 net/socket.c 7c81fd8bfbaa9732 Arnaldo Carvalho de Melo 2007-03-10 831 70e28ef2c9afebab WingMan Kwok 2018-03-02 832 void __sock_recv_redinfo_timestamp(struct msghdr *msg, struct sock *sk, 70e28ef2c9afebab WingMan Kwok 2018-03-02 833 struct sk_buff *skb) 70e28ef2c9afebab WingMan Kwok 2018-03-02 834 { 70e28ef2c9afebab WingMan Kwok 2018-03-02 835 struct scm_timestamping tss; 70e28ef2c9afebab WingMan Kwok 2018-03-02 836 int empty = 1; 70e28ef2c9afebab WingMan Kwok 2018-03-02 837 struct skb_shared_hwtstamps *red_shhwtstamps = 70e28ef2c9afebab WingMan Kwok 2018-03-02 838 skb_redinfo_hwtstamps(skb); 70e28ef2c9afebab WingMan Kwok 2018-03-02 839 70e28ef2c9afebab WingMan Kwok 2018-03-02 840 if (red_shhwtstamps && 70e28ef2c9afebab WingMan Kwok 2018-03-02 841 (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) && 70e28ef2c9afebab WingMan Kwok 2018-03-02 842 ktime_to_timespec_cond(red_shhwtstamps->hwtstamp, tss.ts + 2)) 70e28ef2c9afebab WingMan Kwok 2018-03-02 843 empty = 0; 70e28ef2c9afebab WingMan Kwok 2018-03-02 844 70e28ef2c9afebab WingMan Kwok 2018-03-02 845 if (!empty) 70e28ef2c9afebab WingMan Kwok 2018-03-02 846 put_cmsg(msg, SOL_SOCKET, 70e28ef2c9afebab WingMan Kwok 2018-03-02 @847 SCM_RED_TIMESTAMPING, sizeof(tss), &tss); 70e28ef2c9afebab WingMan Kwok 2018-03-02 848 } 70e28ef2c9afebab WingMan Kwok 2018-03-02 849 EXPORT_SYMBOL_GPL(__sock_recv_redinfo_timestamp); 70e28ef2c9afebab WingMan Kwok 2018-03-02 850 :::::: The code at line 847 was first introduced by commit :::::: 70e28ef2c9afebab74651ba7aca5895ca4d922d4 net: socket: forward extra timestamp of received skb to user space :::::: TO: WingMan Kwok <w-kwok2(a)ti.com&gt; :::::: CC: Lokesh Vutla <lokeshvutla(a)ti.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org