[kbuild-all] [net-next:master 75/126] include/linux/fortify-string.h:27:30: warning: '__builtin_strncpy' output truncated before terminating nul copying as many bytes from a string as its length

tree: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git master head: 77091933e453a258bbe9ff2aeb1c8d6fc1db7ef9 commit: 1556ea9120ffcf4faf7ac6b62a6e28216f260a23 [75/126] net: hns3: refactor dump mac list of debugfs config: mips-allyesconfig (attached as .config) compiler: mips-linux-gcc (GCC) 9.3.0 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://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit... git remote add net-next https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git git fetch --no-tags net-next master git checkout 1556ea9120ffcf4faf7ac6b62a6e28216f260a23 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross W=1 ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): In file included from include/linux/string.h:269, from include/linux/bitmap.h:10, from include/linux/cpumask.h:12, from arch/mips/include/asm/processor.h:15, from arch/mips/include/asm/thread_info.h:16, from include/linux/thread_info.h:59, from include/asm-generic/current.h:5, from ./arch/mips/include/generated/asm/current.h:1, from include/linux/sched.h:12, from include/linux/ratelimit.h:6, from include/linux/dev_printk.h:16, from include/linux/device.h:15, from drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c:4: In function 'strncpy', inlined from 'hclge_dbg_fill_content.constprop' at drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c:88:4: 27 | #define __underlying_strncpy __builtin_strncpy | ^ include/linux/fortify-string.h:38:9: note: in expansion of macro '__underlying_strncpy' 38 | return __underlying_strncpy(p, q, size); | ^~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c: In function 'hclge_dbg_fill_content.constprop': include/linux/fortify-string.h:25:29: note: length computed here 25 | #define __underlying_strlen __builtin_strlen | ^ include/linux/fortify-string.h:60:10: note: in expansion of macro '__underlying_strlen' 60 | return __underlying_strlen(p); | ^~~~~~~~~~~~~~~~~~~ vim +/__builtin_strncpy +27 include/linux/fortify-string.h a28a6e860c6cf2 Francis Laniel 2021-02-25 4 a28a6e860c6cf2 Francis Laniel 2021-02-25 5 a28a6e860c6cf2 Francis Laniel 2021-02-25 6 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) a28a6e860c6cf2 Francis Laniel 2021-02-25 7 extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr); a28a6e860c6cf2 Francis Laniel 2021-02-25 8 extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp); a28a6e860c6cf2 Francis Laniel 2021-02-25 9 extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy); a28a6e860c6cf2 Francis Laniel 2021-02-25 10 extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove); a28a6e860c6cf2 Francis Laniel 2021-02-25 11 extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset); a28a6e860c6cf2 Francis Laniel 2021-02-25 12 extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat); a28a6e860c6cf2 Francis Laniel 2021-02-25 13 extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy); a28a6e860c6cf2 Francis Laniel 2021-02-25 14 extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen); a28a6e860c6cf2 Francis Laniel 2021-02-25 15 extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat); a28a6e860c6cf2 Francis Laniel 2021-02-25 16 extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy); a28a6e860c6cf2 Francis Laniel 2021-02-25 17 #else a28a6e860c6cf2 Francis Laniel 2021-02-25 18 #define __underlying_memchr __builtin_memchr a28a6e860c6cf2 Francis Laniel 2021-02-25 19 #define __underlying_memcmp __builtin_memcmp a28a6e860c6cf2 Francis Laniel 2021-02-25 20 #define __underlying_memcpy __builtin_memcpy a28a6e860c6cf2 Francis Laniel 2021-02-25 21 #define __underlying_memmove __builtin_memmove a28a6e860c6cf2 Francis Laniel 2021-02-25 22 #define __underlying_memset __builtin_memset a28a6e860c6cf2 Francis Laniel 2021-02-25 23 #define __underlying_strcat __builtin_strcat a28a6e860c6cf2 Francis Laniel 2021-02-25 24 #define __underlying_strcpy __builtin_strcpy a28a6e860c6cf2 Francis Laniel 2021-02-25 25 #define __underlying_strlen __builtin_strlen a28a6e860c6cf2 Francis Laniel 2021-02-25 26 #define __underlying_strncat __builtin_strncat a28a6e860c6cf2 Francis Laniel 2021-02-25 @27 #define __underlying_strncpy __builtin_strncpy a28a6e860c6cf2 Francis Laniel 2021-02-25 28 #endif a28a6e860c6cf2 Francis Laniel 2021-02-25 29 :::::: The code at line 27 was first introduced by commit :::::: a28a6e860c6cf231cf3c5171c75c342adcd00406 string.h: move fortified functions definitions in a dedicated header. :::::: TO: Francis Laniel <laniel_francis(a)privacyrequired.com&gt; :::::: CC: Linus Torvalds <torvalds(a)linux-foundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org