Hi Reji, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v5.9 next-20201013] [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/Reji-Thomas/IPv6-sr-Fix-End-X-nexthop-to-use-oif/20201013-204935 base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 865c50e1d279671728c2936cb7680eb89355eeea config: riscv-randconfig-r035-20201014 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project e7fe3c6dfede8d5781bd000741c3dea7088307a4) 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 riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://github.com/0day-ci/linux/commit/8d40085b9b014197ce7a7e8927730796bf50adb0 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Reji-Thomas/IPv6-sr-Fix-End-X-nexthop-to-use-oif/20201013-204935 git checkout 8d40085b9b014197ce7a7e8927730796bf50adb0 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): In file included from net/ipv6/seg6_local.c:11: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:11: In file included from include/linux/scatterlist.h:9: In file included from arch/riscv/include/asm/io.h:148: include/asm-generic/io.h:556:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return inb(addr); ^~~~~~~~~ arch/riscv/include/asm/io.h:54:76: note: expanded from macro 'inb' #define inb(c) ({ u8 __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:87:48: note: expanded from macro 'readb_cpu' #define readb_cpu(c) ({ u8 __r = __raw_readb(c); __r; }) ^ In file included from net/ipv6/seg6_local.c:11: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:11: In file included from include/linux/scatterlist.h:9: In file included from arch/riscv/include/asm/io.h:148: include/asm-generic/io.h:564:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return inw(addr); ^~~~~~~~~ arch/riscv/include/asm/io.h:55:76: note: expanded from macro 'inw' #define inw(c) ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:88:76: note: expanded from macro 'readw_cpu' #define readw_cpu(c) ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; }) ^ include/uapi/linux/byteorder/little_endian.h:36:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from net/ipv6/seg6_local.c:11: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:11: In file included from include/linux/scatterlist.h:9: In file included from arch/riscv/include/asm/io.h:148: include/asm-generic/io.h:572:9: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return inl(addr); ^~~~~~~~~ arch/riscv/include/asm/io.h:56:76: note: expanded from macro 'inl' #define inl(c) ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:89:76: note: expanded from macro 'readl_cpu' #define readl_cpu(c) ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; }) ^ include/uapi/linux/byteorder/little_endian.h:34:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from net/ipv6/seg6_local.c:11: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:11: In file included from include/linux/scatterlist.h:9: In file included from arch/riscv/include/asm/io.h:148: include/asm-generic/io.h:580:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outb(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:58:68: note: expanded from macro 'outb' #define outb(v,c) ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:91:52: note: expanded from macro 'writeb_cpu' #define writeb_cpu(v, c) ((void)__raw_writeb((v), (c))) ^ In file included from net/ipv6/seg6_local.c:11: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:11: In file included from include/linux/scatterlist.h:9: In file included from arch/riscv/include/asm/io.h:148: include/asm-generic/io.h:588:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outw(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:59:68: note: expanded from macro 'outw' #define outw(v,c) ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:92:76: note: expanded from macro 'writew_cpu' #define writew_cpu(v, c) ((void)__raw_writew((__force u16)cpu_to_le16(v), (c))) ^ In file included from net/ipv6/seg6_local.c:11: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:11: In file included from include/linux/scatterlist.h:9: In file included from arch/riscv/include/asm/io.h:148: include/asm-generic/io.h:596:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] outl(value, addr); ^~~~~~~~~~~~~~~~~ arch/riscv/include/asm/io.h:60:68: note: expanded from macro 'outl' #define outl(v,c) ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) ~~~~~~~~~~ ^ arch/riscv/include/asm/mmio.h:93:76: note: expanded from macro 'writel_cpu' #define writel_cpu(v, c) ((void)__raw_writel((__force u32)cpu_to_le32(v), (c))) ^ In file included from net/ipv6/seg6_local.c:11: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:11: In file included from include/linux/scatterlist.h:9: In file included from arch/riscv/include/asm/io.h:148: include/asm-generic/io.h:1017:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port; ~~~~~~~~~~ ^ >> net/ipv6/seg6_local.c:222:5: warning: no previous prototype for function 'seg6_strict_lookup_nexthop' [-Wmissing-prototypes] int seg6_strict_lookup_nexthop(struct sk_buff *skb, ^ net/ipv6/seg6_local.c:222:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int seg6_strict_lookup_nexthop(struct sk_buff *skb, ^ static 8 warnings generated. vim +/seg6_strict_lookup_nexthop +222 net/ipv6/seg6_local.c 221 > 222 int seg6_strict_lookup_nexthop(struct sk_buff *skb, 223 struct in6_addr *nhaddr, int oif, u32 tbl_id) 224 { 225 return seg6_lookup_any_nexthop(skb, nhaddr, oif, tbl_id, false); 226 } 227 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org