Hi Brian, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: ee9bda616d36d2dc864aa294c2656fad88c9efa0 commit: 1fad8422c98999f049d35724a1483cbd3927b8e8 [7051/13214] mmc: sdhci-brcmstb: Allow building with COMPILE_TEST config: hexagon-randconfig-r015-20221206 compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 6e4cea55f0d1104408b26ac574566a0e4de48036) 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/next/linux-next.git/commit/?id=1fad8422c98999f049d35724a1483cbd3927b8e8 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 1fad8422c98999f049d35724a1483cbd3927b8e8 # 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=hexagon SHELL=/bin/bash drivers/mmc/host/ 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/hexagon/include/asm/io.h:334: 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/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(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/hexagon/include/asm/io.h:334: 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/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(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/hexagon/include/asm/io.h:334: 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); ~~~~~~~~~~ ^ >> drivers/mmc/host/sdhci-brcmstb.c:182:34: warning: unused variable 'sdhci_brcm_of_match' [-Wunused-const-variable] static const struct of_device_id sdhci_brcm_of_match[] = { ^ 7 warnings generated. vim +/sdhci_brcm_of_match +182 drivers/mmc/host/sdhci-brcmstb.c 78ab82fdb65c70 Al Cooper 2020-01-13 181 78ab82fdb65c70 Al Cooper 2020-01-13 @182 static const struct of_device_id sdhci_brcm_of_match[] = { 78ab82fdb65c70 Al Cooper 2020-01-13 183 { .compatible = "brcm,bcm7425-sdhci", .data = &match_priv_7425 }, 78ab82fdb65c70 Al Cooper 2020-01-13 184 { .compatible = "brcm,bcm7445-sdhci", .data = &match_priv_7445 }, 78ab82fdb65c70 Al Cooper 2020-01-13 185 { .compatible = "brcm,bcm7216-sdhci", .data = &match_priv_7216 }, 78ab82fdb65c70 Al Cooper 2020-01-13 186 {}, 78ab82fdb65c70 Al Cooper 2020-01-13 187 }; 78ab82fdb65c70 Al Cooper 2020-01-13 188 :::::: The code at line 182 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