Hi Mauro, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 0a71553536d270e988580a3daa9fc87535908221 commit: 2023a99811110aebba9eee4aa09ef7bd21a8a249 media: platform: rename mediatek/mtk-jpeg/ to mediatek/jpeg/ date: 10 months ago config: s390-randconfig-r005-20230107 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=2023a99811110aebba9eee4aa09ef7bd21a8a249 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 2023a99811110aebba9eee4aa09ef7bd21a8a249 # 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/media/platform/ 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/media/platform/mediatek/mdp/mtk_mdp_core.c:15: In file included from include/linux/of_address.h:7: 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: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: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/media/platform/mediatek/mdp/mtk_mdp_core.c:15: In file included from include/linux/of_address.h:7: 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: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: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/media/platform/mediatek/mdp/mtk_mdp_core.c:15: In file included from include/linux/of_address.h:7: 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: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); ~~~~~~~~~~ ^ >> drivers/media/platform/mediatek/mdp/mtk_mdp_core.c:31:34: warning: unused variable 'mtk_mdp_comp_dt_ids' [-Wunused-const-variable] static const struct of_device_id mtk_mdp_comp_dt_ids[] = { ^ 13 warnings generated. vim +/mtk_mdp_comp_dt_ids +31 drivers/media/platform/mediatek/mdp/mtk_mdp_core.c c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 30 c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 @31 static const struct of_device_id mtk_mdp_comp_dt_ids[] = { c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 32 { c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 33 .compatible = "mediatek,mt8173-mdp-rdma", c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 34 .data = (void *)MTK_MDP_RDMA c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 35 }, { c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 36 .compatible = "mediatek,mt8173-mdp-rsz", c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 37 .data = (void *)MTK_MDP_RSZ c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 38 }, { c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 39 .compatible = "mediatek,mt8173-mdp-wdma", c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 40 .data = (void *)MTK_MDP_WDMA c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 41 }, { c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 42 .compatible = "mediatek,mt8173-mdp-wrot", c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 43 .data = (void *)MTK_MDP_WROT 55d80506c5f7c3 drivers/media/platform/mtk-mdp/mtk_mdp_core.c Vincent Stehlé 2016-10-27 44 }, 55d80506c5f7c3 drivers/media/platform/mtk-mdp/mtk_mdp_core.c Vincent Stehlé 2016-10-27 45 { }, c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 46 }; c8eb2d7e8202fd drivers/media/platform/mtk-mdp/mtk_mdp_core.c Minghsiu Tsai 2016-09-08 47 :::::: The code at line 31 was first introduced by commit :::::: c8eb2d7e8202fd9cb912f5d33cc34ede66dcb24a [media] media: Add Mediatek MDP Driver :::::: TO: Minghsiu Tsai :::::: CC: Mauro Carvalho Chehab -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests