Hi Neal, First bad commit (maybe != root cause): tree: https://github.com/zen-kernel/zen-kernel 5.10/bbr2 head: b9dd14514a5879eee40822e28074dcc6a12e12b8 commit: ba575c2fd7855b0586a87bbc6a67e1fa7fd397a1 [14/27] net-tcp: re-generalize TSO sizing in TCP CC module API config: sh-allmodconfig (attached as .config) compiler: sh4-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 # https://github.com/zen-kernel/zen-kernel/commit/ba575c2fd7855b0586a87bbc6... git remote add zen-kernel-zen-kernel https://github.com/zen-kernel/zen-kernel git fetch --no-tags zen-kernel-zen-kernel 5.10/bbr2 git checkout ba575c2fd7855b0586a87bbc6a67e1fa7fd397a1 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sh 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 >>, old ones prefixed by <<): ERROR: modpost: "__delay" [drivers/net/mdio/mdio-cavium.ko] undefined! Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for SND_ATMEL_SOC_PDC Depends on SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC && HAS_DMA Selected by - SND_ATMEL_SOC_SSC && SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC - SND_ATMEL_SOC_SSC_PDC && SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC && ATMEL_SSC --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org