tree: https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git coresched head: ab6dba45b1d05f19d87064315f414761a86ab024 commit: 81ab496aa4fb2f215f7e10edfaaccecc67eef58a [21/27] entry/idle: Enter and exit kernel protection during idle entry and exit config: powerpc-randconfig-r032-20201214 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project a29ecca7819a6ed4250d3689b12b1f664bb790d7) 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 # install powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git/commit/?i... git remote add jfern https://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git git fetch --no-tags jfern coresched git checkout 81ab496aa4fb2f215f7e10edfaaccecc67eef58a # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang 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 >>): In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:45:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(insw, (unsigned long p, void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:166:1: note: expanded from here __do_insw ^ arch/powerpc/include/asm/io.h:542:56: note: expanded from macro '__do_insw' #define __do_insw(p, b, n) readsw((PCI_IO_ADDR)_IO_BASE+(p), (b), (n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:47:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(insl, (unsigned long p, void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:168:1: note: expanded from here __do_insl ^ arch/powerpc/include/asm/io.h:543:56: note: expanded from macro '__do_insl' #define __do_insl(p, b, n) readsl((PCI_IO_ADDR)_IO_BASE+(p), (b), (n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:49:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(outsb, (unsigned long p, const void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:170:1: note: expanded from here __do_outsb ^ arch/powerpc/include/asm/io.h:544:58: note: expanded from macro '__do_outsb' #define __do_outsb(p, b, n) writesb((PCI_IO_ADDR)_IO_BASE+(p),(b),(n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:51:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(outsw, (unsigned long p, const void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:172:1: note: expanded from here __do_outsw ^ arch/powerpc/include/asm/io.h:545:58: note: expanded from macro '__do_outsw' #define __do_outsw(p, b, n) writesw((PCI_IO_ADDR)_IO_BASE+(p),(b),(n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from kernel/sched/idle.c:9: In file included from kernel/sched/sched.h:17: In file included from include/linux/sched/isolation.h:6: In file included from include/linux/tick.h:8: In file included from include/linux/clockchips.h:14: In file included from include/linux/clocksource.h:21: In file included from arch/powerpc/include/asm/io.h:604: arch/powerpc/include/asm/io-defs.h:53:1: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] DEF_PCI_AC_NORET(outsl, (unsigned long p, const void *b, unsigned long c), ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ arch/powerpc/include/asm/io.h:601:3: note: expanded from macro 'DEF_PCI_AC_NORET' __do_##name al; \ ^~~~~~~~~~~~~~ <scratch space>:174:1: note: expanded from here __do_outsl ^ arch/powerpc/include/asm/io.h:546:58: note: expanded from macro '__do_outsl' #define __do_outsl(p, b, n) writesl((PCI_IO_ADDR)_IO_BASE+(p),(b),(n)) ~~~~~~~~~~~~~~~~~~~~~^ In file included from kernel/sched/idle.c:9: kernel/sched/sched.h:1232:17: warning: declaration of 'struct sched_group' will not be visible outside of this function [-Wvisibility] struct sched_group *group) ^ In file included from kernel/sched/idle.c:11: #include <asm/entry-common.h> ^~~~~~~~~~~~~~~~~~~~ 13 warnings and 1 error generated. vim +10 include/linux/entry-common.h 142781e108b13b2 Thomas Gleixner 2020-07-22 9 142781e108b13b2 Thomas Gleixner 2020-07-22 @10 #include <asm/entry-common.h> 142781e108b13b2 Thomas Gleixner 2020-07-22 11 :::::: The code at line 10 was first introduced by commit :::::: 142781e108b13b2b0e8f035cfb5bfbbc8f14d887 entry: Provide generic syscall entry functionality :::::: TO: Thomas Gleixner <tglx(a)linutronix.de&gt; :::::: CC: Thomas Gleixner <tglx(a)linutronix.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org