tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git master head: e1d9d7b91302593d1951fcb12feddda6fb58a3c0 commit: 85ce50d337d10a6fd328fa70b0a15543bf5c0f64 [181/184] net: kcov: don't select SKB_EXTENSIONS when there is no NET config: s390-randconfig-r036-20201113 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 9e0c35655b6e8186baef8840b26ba4090503b554) 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/netdev/net-next.git/commi... git remote add netdev-net-next https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git git fetch --no-tags netdev-net-next master git checkout 85ce50d337d10a6fd328fa70b0a15543bf5c0f64 # 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 <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): 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 arch/s390/kernel/asm-offsets.c:11: In file included from include/linux/kvm_host.h:32: In file included from include/linux/kvm_para.h:5: In file included from include/uapi/linux/kvm_para.h:36: In file included from arch/s390/include/asm/kvm_para.h:25: In file included from arch/s390/include/asm/diag.h:12: In file included from include/linux/if_ether.h:19: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: 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 arch/s390/kernel/asm-offsets.c:11: In file included from include/linux/kvm_host.h:32: In file included from include/linux/kvm_para.h:5: In file included from include/uapi/linux/kvm_para.h:36: In file included from arch/s390/include/asm/kvm_para.h:25: In file included from arch/s390/include/asm/diag.h:12: In file included from include/linux/if_ether.h:19: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: 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 arch/s390/kernel/asm-offsets.c:11: In file included from include/linux/kvm_host.h:32: In file included from include/linux/kvm_para.h:5: In file included from include/uapi/linux/kvm_para.h:36: In file included from arch/s390/include/asm/kvm_para.h:25: In file included from arch/s390/include/asm/diag.h:12: In file included from include/linux/if_ether.h:19: In file included from include/linux/skbuff.h:31: In file included from include/linux/dma-mapping.h:10: In file included from include/linux/scatterlist.h:9: 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); ~~~~~~~~~~ ^ In file included from arch/s390/kernel/asm-offsets.c:11: In file included from include/linux/kvm_host.h:32: In file included from include/linux/kvm_para.h:5: In file included from include/uapi/linux/kvm_para.h:36: In file included from arch/s390/include/asm/kvm_para.h:25: In file included from arch/s390/include/asm/diag.h:12: In file included from include/linux/if_ether.h:19: u64 *kcov_handle_ptr = skb_ext_add(skb, SKB_EXT_KCOV_HANDLE); ^ u64 *kcov_handle_ptr = skb_ext_add(skb, SKB_EXT_KCOV_HANDLE); ^ u64 *kcov_handle = skb_ext_find(skb, SKB_EXT_KCOV_HANDLE); ^ include/linux/skbuff.h:4631:39: error: use of undeclared identifier 'SKB_EXT_KCOV_HANDLE' u64 *kcov_handle = skb_ext_find(skb, SKB_EXT_KCOV_HANDLE); ^ 20 warnings and 4 errors generated. make[2]: *** [scripts/Makefile.build:117: arch/s390/kernel/asm-offsets.s] Error 1 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1200: prepare0] Error 2 make[1]: Target 'prepare' not remade because of errors. make: *** [Makefile:185: __sub-make] Error 2 make: Target 'prepare' not remade because of errors. vim +/skb_ext_add +4622 include/linux/skbuff.h 2c64605b590edad Pablo Neira Ayuso 2020-03-25 4610 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4611 #ifdef CONFIG_KCOV 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4612 static inline void skb_set_kcov_handle(struct sk_buff *skb, 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4613 const u64 kcov_handle) 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4614 { 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4615 /* Do not allocate skb extensions only to set kcov_handle to zero 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4616 * (as it is zero by default). However, if the extensions are 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4617 * already allocated, update kcov_handle anyway since 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4618 * skb_set_kcov_handle can be called to zero a previously set 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4619 * value. 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4620 */ 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4621 if (skb_has_extensions(skb) || kcov_handle) { 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 @4622 u64 *kcov_handle_ptr = skb_ext_add(skb, SKB_EXT_KCOV_HANDLE); 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4623 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4624 if (kcov_handle_ptr) 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4625 *kcov_handle_ptr = kcov_handle; 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4626 } 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4627 } 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4628 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4629 static inline u64 skb_get_kcov_handle(struct sk_buff *skb) 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4630 { 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 @4631 u64 *kcov_handle = skb_ext_find(skb, SKB_EXT_KCOV_HANDLE); 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4632 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4633 return kcov_handle ? *kcov_handle : 0; 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4634 } 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4635 #else 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4636 static inline void skb_set_kcov_handle(struct sk_buff *skb, 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4637 const u64 kcov_handle) { } 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4638 static inline u64 skb_get_kcov_handle(struct sk_buff *skb) { return 0; } 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4639 #endif /* CONFIG_KCOV */ 6370cc3bbd8a0f9 Aleksandr Nogikh 2020-10-29 4640 :::::: The code at line 4622 was first introduced by commit :::::: 6370cc3bbd8a0f9bf975b013781243ab147876c6 net: add kcov handle to skb extensions :::::: TO: Aleksandr Nogikh <nogikh(a)google.com&gt; :::::: CC: Jakub Kicinski <kuba(a)kernel.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org