Hi Max, I love your patch! Yet something to improve: [auto build test ERROR on vhost/linux-next] [also build test ERROR on linus/master v5.12-rc6 next-20210407] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Max-Gurtovoy/virtio-update-reset-callback-to-return-status/20210407-201026 base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next config: s390-randconfig-r032-20210407 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project c060945b23a1c54d4b2a053ff4b093a2277b303d) 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://github.com/0day-ci/linux/commit/74d4580725028f138a4713e8594f9068e9c83805 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Max-Gurtovoy/virtio-update-reset-callback-to-return-status/20210407-201026 git checkout 74d4580725028f138a4713e8594f9068e9c83805 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x)) ^ include/uapi/linux/swab.h:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:19:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \ ^ In file included from drivers/s390/virtio/virtio_ccw.c:12: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: 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:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:20:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \ ^ In file included from drivers/s390/virtio/virtio_ccw.c:12: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: 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:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:21:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \ ^ In file included from drivers/s390/virtio/virtio_ccw.c:12: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: 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:119:21: note: expanded from macro '__swab32' ___constant_swab32(x) : \ ^ include/uapi/linux/swab.h:22:12: note: expanded from macro '___constant_swab32' (((__u32)(x) & (__u32)0xff000000UL) >> 24))) ^ In file included from drivers/s390/virtio/virtio_ccw.c:12: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: 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:120:12: note: expanded from macro '__swab32' __fswab32(x)) ^ In file included from drivers/s390/virtio/virtio_ccw.c:12: In file included from include/linux/memblock.h:14: In file included from arch/s390/include/asm/dma.h:5: 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); ~~~~~~~~~~ ^ >> drivers/s390/virtio/virtio_ccw.c:1016:11: error: incompatible function pointer types initializing 'int (*)(struct virtio_device *)' with an expression of type 'void (struct virtio_device *)' [-Werror,-Wincompatible-function-pointer-types] .reset = virtio_ccw_reset, ^~~~~~~~~~~~~~~~ 20 warnings and 1 error generated. vim +1016 drivers/s390/virtio/virtio_ccw.c 971bedca26e037 drivers/s390/virtio/virtio_ccw.c Cornelia Huck 2019-01-21 1008 0db1dba5dfaf70 drivers/s390/virtio/virtio_ccw.c Bhumika Goyal 2017-01-14 1009 static const struct virtio_config_ops virtio_ccw_config_ops = { 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1010 .get_features = virtio_ccw_get_features, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1011 .finalize_features = virtio_ccw_finalize_features, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1012 .get = virtio_ccw_get_config, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1013 .set = virtio_ccw_set_config, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1014 .get_status = virtio_ccw_get_status, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1015 .set_status = virtio_ccw_set_status, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 @1016 .reset = virtio_ccw_reset, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1017 .find_vqs = virtio_ccw_find_vqs, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1018 .del_vqs = virtio_ccw_del_vqs, 971bedca26e037 drivers/s390/virtio/virtio_ccw.c Cornelia Huck 2019-01-21 1019 .bus_name = virtio_ccw_bus_name, 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1020 }; 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1021 7e64e0597fd67c drivers/s390/kvm/virtio_ccw.c Cornelia Huck 2012-12-14 1022 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org