Hi Stanislav, I love your patch! Perhaps something to improve: [auto build test WARNING on bpf-next/master] url: https://github.com/intel-lab-lkp/linux/commits/Stanislav-Fomichev/xdp-hints-via-kfuncs/20221115-110547 base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master patch link: https://lore.kernel.org/r/20221115030210.3159213-7-sdf%40google.com patch subject: [PATCH bpf-next 06/11] xdp: Carry over xdp metadata into skb context config: hexagon-randconfig-r031-20221115 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 # https://github.com/intel-lab-lkp/linux/commit/5c7e4e60d13af8491563dd4d2ad5fc684420e540 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Stanislav-Fomichev/xdp-hints-via-kfuncs/20221115-110547 git checkout 5c7e4e60d13af8491563dd4d2ad5fc684420e540 # 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 net/sched/ 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 net/sched/cls_flow.c:14: In file included from include/linux/skbuff.h:17: In file included from include/linux/bvec.h:10: In file included from include/linux/highmem.h:12: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: 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 net/sched/cls_flow.c:14: In file included from include/linux/skbuff.h:17: In file included from include/linux/bvec.h:10: In file included from include/linux/highmem.h:12: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: 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 net/sched/cls_flow.c:14: In file included from include/linux/skbuff.h:17: In file included from include/linux/bvec.h:10: In file included from include/linux/highmem.h:12: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: 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); ~~~~~~~~~~ ^ In file included from net/sched/cls_flow.c:17: In file included from include/linux/ipv6.h:93: In file included from include/linux/tcp.h:19: In file included from include/net/sock.h:46: In file included from include/linux/netdevice.h:43: include/net/xdp.h:449:2: error: void function 'xdp_metadata_export_to_skb' should not return a value [-Wreturn-type] return 0; ^ ~ >> net/sched/cls_flow.c:63:52: warning: shift count >= width of type [-Wshift-count-overflow] return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0); ^ ~~ 7 warnings and 1 error generated. vim +63 net/sched/cls_flow.c e5dfb815181fcb Patrick McHardy 2008-01-31 58 e5dfb815181fcb Patrick McHardy 2008-01-31 59 static inline u32 addr_fold(void *addr) e5dfb815181fcb Patrick McHardy 2008-01-31 60 { e5dfb815181fcb Patrick McHardy 2008-01-31 61 unsigned long a = (unsigned long)addr; e5dfb815181fcb Patrick McHardy 2008-01-31 62 e5dfb815181fcb Patrick McHardy 2008-01-31 @63 return (a & 0xFFFFFFFF) ^ (BITS_PER_LONG > 32 ? a >> 32 : 0); e5dfb815181fcb Patrick McHardy 2008-01-31 64 } e5dfb815181fcb Patrick McHardy 2008-01-31 65 -- 0-DAY CI Kernel Test Service https://01.org/lkp