Hi Brian, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 15f3bff12cf6a888ec2ad39652828c60e6836b3d commit: b4619aac26fa33f8bd85cada87fa3195336a4aeb [5070/8327] mmc: sdhci-brcmstb: Allow building with COMPILE_TEST config: s390-randconfig-c005-20221116 compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 463da45892e2d2a262277b91b96f5f8c05dc25d0) 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/next/linux-next.git/commit/?id=b4619aac26fa33f8bd85cada87fa3195336a4aeb git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout b4619aac26fa33f8bd85cada87fa3195336a4aeb # 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 SHELL=/bin/bash drivers/mmc/host/ drivers/phy/ drivers/soc/qcom/ If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from drivers/mmc/host/sdhci-brcmstb.c:8: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:547:31: 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:560:61: 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: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/mmc/host/sdhci-brcmstb.c:8: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:573:61: 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: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/mmc/host/sdhci-brcmstb.c:8: In file included from include/linux/io.h:13: In file included from arch/s390/include/asm/io.h:75: include/asm-generic/io.h:584:33: 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:594:59: 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:604:59: 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:692:20: 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:700:20: 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:708:20: 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:717:21: 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:726:21: 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:735:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] writesl(PCI_IOBASE + addr, buffer, count); ~~~~~~~~~~ ^ >> drivers/mmc/host/sdhci-brcmstb.c:181:34: warning: unused variable 'sdhci_brcm_of_match' [-Wunused-const-variable] static const struct of_device_id sdhci_brcm_of_match[] = { ^ 13 warnings generated. vim +/sdhci_brcm_of_match +181 drivers/mmc/host/sdhci-brcmstb.c 78ab82fdb65c70 Al Cooper 2020-01-13 180 78ab82fdb65c70 Al Cooper 2020-01-13 @181 static const struct of_device_id sdhci_brcm_of_match[] = { 78ab82fdb65c70 Al Cooper 2020-01-13 182 { .compatible = "brcm,bcm7425-sdhci", .data = &match_priv_7425 }, 78ab82fdb65c70 Al Cooper 2020-01-13 183 { .compatible = "brcm,bcm7445-sdhci", .data = &match_priv_7445 }, 78ab82fdb65c70 Al Cooper 2020-01-13 184 { .compatible = "brcm,bcm7216-sdhci", .data = &match_priv_7216 }, 78ab82fdb65c70 Al Cooper 2020-01-13 185 {}, 78ab82fdb65c70 Al Cooper 2020-01-13 186 }; 78ab82fdb65c70 Al Cooper 2020-01-13 187 :::::: The code at line 181 was first introduced by commit :::::: 78ab82fdb65c703fa21db348c50c3f3eae773d62 mmc: sdhci-brcmstb: Add ability to use HS400ES transfer mode :::::: TO: Al Cooper :::::: CC: Ulf Hansson -- 0-DAY CI Kernel Test Service https://01.org/lkp