Hi Jessica, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild.git kbuild head: 3a9dd3ecb207b2cb8a4aabd12d20e43fa360b66d commit: 93c95e526a4ef00eb3d5a1e0920ba5a22f32e40d [16/20] modpost: rework and consolidate logging interface config: openrisc-randconfig-a001-20200313 (attached as .config) compiler: or1k-linux-gcc (GCC) 9.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross git checkout 93c95e526a4ef00eb3d5a1e0920ba5a22f32e40d # save the attached .config to linux build tree GCC_VERSION=9.2.0 make.cross ARCH=openrisc If you fix the issue, kindly add following tag Reported-by: kbuild test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): ERROR: modpost: "__mulsi3" [lib/raid6/raid6_pq.ko] undefined! ERROR: modpost: "__mulsi3" [lib/zstd/zstd_decompress.ko] undefined! ERROR: modpost: "__mulsi3" [lib/zstd/zstd_compress.ko] undefined! ERROR: modpost: "__mulsi3" [lib/test_bpf.ko] undefined! ERROR: modpost: "__mulsi3" [lib/math/prime_numbers.ko] undefined! ERROR: modpost: "__mulsi3" [net/sunrpc/auth_gss/auth_rpcgss.ko] undefined! ERROR: modpost: "__mulsi3" [drivers/media/rc/rc-loopback.ko] undefined! ERROR: modpost: "__mulsi3" [drivers/media/rc/rc-core.ko] undefined! ERROR: modpost: "__mulsi3" [drivers/net/veth.ko] undefined! ERROR: modpost: "__mulsi3" [drivers/gpu/drm/selftests/test-drm_modeset.ko] undefined! ERROR: modpost: "__mulsi3" [drivers/gpu/drm/selftests/test-drm_mm.ko] undefined! ERROR: modpost: "__mulsi3" [drivers/gpu/drm/bridge/sil-sii8620.ko] undefined! ERROR: modpost: "__mulsi3" [crypto/xor.ko] undefined! ERROR: modpost: "__mulsi3" [fs/btrfs/btrfs.ko] undefined! ERROR: modpost: "__mulsi3" [fs/xfs/xfs.ko] undefined! ERROR: modpost: "__mulsi3" [fs/cifs/cifs.ko] undefined! ERROR: modpost: "__mulsi3" [fs/pstore/ramoops.ko] undefined! ERROR: modpost: "__mulsi3" [fs/nfs/nfsv4.ko] undefined! ERROR: modpost: "__mulsi3" [kernel/locking/test-ww_mutex.ko] undefined! --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org