tree: git://anongit.freedesktop.org/drm/drm-misc drm-misc-next head: 04dfe19a5ed683e91d8285df5be1dbde2f2f39af commit: 04dfe19a5ed683e91d8285df5be1dbde2f2f39af [4/4] drm: Mark AGP implementation and ioctls as legacy config: s390-randconfig-r012-20210510 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 492173d42b32cb91d5d0d72d5ed84fcab80d059a) 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 s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu git remote add drm-drm-misc git://anongit.freedesktop.org/drm/drm-misc git fetch --no-tags drm-drm-misc drm-misc-next git checkout 04dfe19a5ed683e91d8285df5be1dbde2f2f39af # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=s390 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 drivers/gpu/drm/drm_agpsupport.c:35: In file included from include/linux/pci.h:39: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:36:59: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x)) ^ include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16' #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) ^ In file included from drivers/gpu/drm/drm_agpsupport.c:35: In file included from include/linux/pci.h:39: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32' #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x)) ^ In file included from drivers/gpu/drm/drm_agpsupport.c:35: In file included from include/linux/pci.h:39: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:80: include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ #include <asm/agp.h> ^~~~~~~~~~~ 12 warnings and 1 error generated. vim +38 drivers/gpu/drm/drm_agpsupport.c ^1da177e4c3f41 drivers/char/drm/drm_agpsupport.c Linus Torvalds 2005-04-16 37 1bb88edb7a3769 drivers/gpu/drm/drm_agpsupport.c Eric Anholt 2009-01-15 @38 #include <asm/agp.h> 1bb88edb7a3769 drivers/gpu/drm/drm_agpsupport.c Eric Anholt 2009-01-15 39 :::::: The code at line 38 was first introduced by commit :::::: 1bb88edb7a3769992026f34fd648bb459b0469aa drm: stash AGP include under the do-we-have-AGP ifdef :::::: TO: Eric Anholt <eric(a)anholt.net&gt; :::::: CC: Dave Airlie <airlied(a)redhat.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org