Hi Thomas, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq/core head: 3bda84519c6c2d57e7378417ac116f61d50abae1 commit: f07147b162a1cec348d8a9a7e7e73fdf7ce5f88b [56/60] genirq: Remove export of irq_to_desc() config: powerpc-allmodconfig (attached as .config) compiler: powerpc64-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://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=f0... git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git git fetch --no-tags tip irq/core git checkout f07147b162a1cec348d8a9a7e7e73fdf7ce5f88b # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=powerpc 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: ".__irq_set_lockdep_class" [drivers/spmi/spmi-pmic-arb.ko] undefined! ERROR: modpost: ".__irq_set_lockdep_class" [drivers/net/dsa/mv88e6xxx/mv88e6xxx.ko] undefined! ERROR: modpost: ".__irq_set_lockdep_class" [drivers/gpio/gpio-brcmstb.ko] undefined! ERROR: modpost: ".__irq_set_lockdep_class" [drivers/pinctrl/pinctrl-single.ko] undefined! --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org