Hi Haijun, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: c757fc92a3f73734872c7793b97f06434773d65d commit: 13e920d93e37fcaef4a9309515798a3cae9dcf19 net: wwan: t7xx: Add core components date: 8 months ago config: s390-randconfig-r003-20230112 compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 8d9828ef5aa9688500657d36cd2aefbe12bbd162) 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 # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=13e920d93e37fcaef4a9309515798a3cae9dcf19 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 13e920d93e37fcaef4a9309515798a3cae9dcf19 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/net/wwan/t7xx/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot All errors (new ones prefixed by >>): In file included from drivers/net/wwan/t7xx/t7xx_pci.c:22: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: >> include/asm-generic/io.h:464:31: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:477:61: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:37:59: 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/net/wwan/t7xx/t7xx_pci.c:22: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:490:61: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/big_endian.h:35:59: 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/net/wwan/t7xx/t7xx_pci.c:22: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:501:33: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:511:59: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:521:59: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:609:20: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] readsb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:617:20: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] readsw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:625:20: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] readsl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:634:21: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] writesb(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:643:21: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] writesw(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ include/asm-generic/io.h:652:21: error: performing pointer arithmetic on a null pointer has undefined behavior [-Werror,-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ 12 errors generated. vim +464 include/asm-generic/io.h 3f7e212df82ca0 Arnd Bergmann 2009-05-13 450 9216efafc52ff9 Thierry Reding 2014-10-01 451 /* 9216efafc52ff9 Thierry Reding 2014-10-01 452 * {in,out}{b,w,l}() access little endian I/O. {in,out}{b,w,l}_p() can be 9216efafc52ff9 Thierry Reding 2014-10-01 453 * implemented on hardware that needs an additional delay for I/O accesses to 9216efafc52ff9 Thierry Reding 2014-10-01 454 * take effect. 9216efafc52ff9 Thierry Reding 2014-10-01 455 */ 9216efafc52ff9 Thierry Reding 2014-10-01 456 f009c89df79abe John Garry 2020-03-28 457 #if !defined(inb) && !defined(_inb) f009c89df79abe John Garry 2020-03-28 458 #define _inb _inb 214ba3584b2e2c Stafford Horne 2020-07-26 459 static inline u8 _inb(unsigned long addr) 9216efafc52ff9 Thierry Reding 2014-10-01 460 { 87fe2d543f8173 Sinan Kaya 2018-04-05 461 u8 val; 87fe2d543f8173 Sinan Kaya 2018-04-05 462 87fe2d543f8173 Sinan Kaya 2018-04-05 463 __io_pbr(); 87fe2d543f8173 Sinan Kaya 2018-04-05 @464 val = __raw_readb(PCI_IOBASE + addr); abbbbc83a210e9 Will Deacon 2019-02-22 465 __io_par(val); 87fe2d543f8173 Sinan Kaya 2018-04-05 466 return val; 9216efafc52ff9 Thierry Reding 2014-10-01 467 } 9216efafc52ff9 Thierry Reding 2014-10-01 468 #endif 9216efafc52ff9 Thierry Reding 2014-10-01 469 :::::: The code at line 464 was first introduced by commit :::::: 87fe2d543f817300e13f0ea683f38c122737856e io: change inX() to have their own IO barrier overrides :::::: TO: Sinan Kaya :::::: CC: Arnd Bergmann -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests