tree: https://gitee.com/openeuler/kernel.git openEuler-1.0-LTS head: 52349611d09c6a9a2b558b3ce1cb1dca0d47dbe8 commit: 7ad207616673722d5cf52c18d9464e0d3184ffc9 [1407/1407] arp: Prevent overflow in arp_req_get(). config: x86_64-defconfig (https://download.01.org/0day-ci/archive/20250118/202501180701.f6sYgGum-lkp@i...) compiler: gcc-11 (Debian 11.3.0-12) 11.3.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250118/202501180701.f6sYgGum-lkp@i...) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202501180701.f6sYgGum-lkp@intel.com/ All warnings (new ones prefixed by >>): In file included from include/linux/list.h:9, from include/linux/module.h:10, from net/ipv4/arp.c:78: net/ipv4/arp.c: In function 'arp_req_get':

...

include/linux/kernel.h:851:43: warning: comparison of distinct pointer types lacks a cast 851 | (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) | ^~ include/linux/kernel.h:865:18: note: in expansion of macro '__typecheck' 865 | (__typecheck(x, y) && __no_side_effects(x, y)) | ^~~~~~~~~~~ include/linux/kernel.h:875:31: note: in expansion of macro '__safe_cmp' 875 | __builtin_choose_expr(__safe_cmp(x, y), \ | ^~~~~~~~~~ include/linux/kernel.h:884:25: note: in expansion of macro '__careful_cmp' 884 | #define min(x, y) __careful_cmp(x, y, <) | ^~~~~~~~~~~~~ net/ipv4/arp.c:1106:33: note: in expansion of macro 'min' 1106 | min(dev->addr_len, sizeof(r->arp_ha.sa_data))); | ^~~ net/ipv4/arp.o: warning: objtool: missing symbol for section .init.text

vim +851 include/linux/kernel.h 526211bc58c4b3 Ingo Molnar 2009-03-05 837 ^1da177e4c3f41 Linus Torvalds 2005-04-16 838 /* 3c8ba0d61d04ce Kees Cook 2018-03-30 839 * min()/max()/clamp() macros must accomplish three things: 3c8ba0d61d04ce Kees Cook 2018-03-30 840 * 3c8ba0d61d04ce Kees Cook 2018-03-30 841 * - avoid multiple evaluations of the arguments (so side-effects like 3c8ba0d61d04ce Kees Cook 2018-03-30 842 * "x++" happen only once) when non-constant. 3c8ba0d61d04ce Kees Cook 2018-03-30 843 * - perform strict type-checking (to generate warnings instead of 3c8ba0d61d04ce Kees Cook 2018-03-30 844 * nasty runtime surprises). See the "unnecessary" pointer comparison 3c8ba0d61d04ce Kees Cook 2018-03-30 845 * in __typecheck(). 3c8ba0d61d04ce Kees Cook 2018-03-30 846 * - retain result as a constant expressions when called with only 3c8ba0d61d04ce Kees Cook 2018-03-30 847 * constant expressions (to avoid tripping VLA warnings in stack 3c8ba0d61d04ce Kees Cook 2018-03-30 848 * allocation usage). 3c8ba0d61d04ce Kees Cook 2018-03-30 849 */ 3c8ba0d61d04ce Kees Cook 2018-03-30 850 #define __typecheck(x, y) \ 3c8ba0d61d04ce Kees Cook 2018-03-30 @851 (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1))) 3c8ba0d61d04ce Kees Cook 2018-03-30 852 :::::: The code at line 851 was first introduced by commit :::::: 3c8ba0d61d04ced9f8d9ff93977995a9e4e96e91 kernel.h: Retain constant expression output for max()/min() :::::: TO: Kees Cook <keescook@chromium.org> :::::: CC: Linus Torvalds <torvalds@linux-foundation.org> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki