[android-common:android11-5.4 1/1] include/linux/string.h:294:30: warning: '__builtin_strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length

[kernel test robot <lkp@intel.com>]

tree:   https://android.googlesource.com/kernel/common android11-5.4
head:   1aec9e76fe4a65b0a26fa1b30bdb3400d9728b2d
commit: 185c2266c1df80bec001c987d64cae2d9cd13816 [1/1] bpf: Fix truncation handling for mod32 dst reg wrt zero
config: arm64-randconfig-004-20250429 (https://download.01.org/0day-ci/archive/20250429/202504290636.O2Uqc8di-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 9.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250429/202504290636.O2Uqc8di-lkp@intel.com/reproduce)

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/202504290636.O2Uqc8di-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from arch/arm64/include/asm/processor.h:28,
                    from include/asm-generic/qrwlock.h:14,
                    from ./arch/arm64/include/generated/asm/qrwlock.h:1,
                    from arch/arm64/include/asm/spinlock.h:8,
                    from include/linux/spinlock.h:89,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:6,
                    from include/linux/slab.h:15,
                    from drivers/nvme/target/discovery.c:7:
   In function 'strncpy',
       inlined from 'nvmet_execute_identify_disc_ctrl' at drivers/nvme/target/discovery.c:243:2:
>> include/linux/string.h:294:30: warning: '__builtin_strncpy' output truncated before terminating nul copying 8 bytes from a string of the same length [-Wstringop-truncation]
     294 | #define __underlying_strncpy __builtin_strncpy
         |                              ^
   include/linux/string.h:304:9: note: in expansion of macro '__underlying_strncpy'
     304 |  return __underlying_strncpy(p, q, size);
         |         ^~~~~~~~~~~~~~~~~~~~


vim +/__builtin_strncpy +294 include/linux/string.h

b008ae4cc74d3a Daniel Axtens 2020-06-03  272  
b008ae4cc74d3a Daniel Axtens 2020-06-03  273  #ifdef CONFIG_KASAN
b008ae4cc74d3a Daniel Axtens 2020-06-03  274  extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
b008ae4cc74d3a Daniel Axtens 2020-06-03  275  extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
b008ae4cc74d3a Daniel Axtens 2020-06-03  276  extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
b008ae4cc74d3a Daniel Axtens 2020-06-03  277  extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
b008ae4cc74d3a Daniel Axtens 2020-06-03  278  extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
b008ae4cc74d3a Daniel Axtens 2020-06-03  279  extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
b008ae4cc74d3a Daniel Axtens 2020-06-03  280  extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
b008ae4cc74d3a Daniel Axtens 2020-06-03  281  extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
b008ae4cc74d3a Daniel Axtens 2020-06-03  282  extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
b008ae4cc74d3a Daniel Axtens 2020-06-03  283  extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
b008ae4cc74d3a Daniel Axtens 2020-06-03  284  #else
b008ae4cc74d3a Daniel Axtens 2020-06-03  285  #define __underlying_memchr	__builtin_memchr
b008ae4cc74d3a Daniel Axtens 2020-06-03  286  #define __underlying_memcmp	__builtin_memcmp
b008ae4cc74d3a Daniel Axtens 2020-06-03  287  #define __underlying_memcpy	__builtin_memcpy
b008ae4cc74d3a Daniel Axtens 2020-06-03  288  #define __underlying_memmove	__builtin_memmove
b008ae4cc74d3a Daniel Axtens 2020-06-03  289  #define __underlying_memset	__builtin_memset
b008ae4cc74d3a Daniel Axtens 2020-06-03  290  #define __underlying_strcat	__builtin_strcat
b008ae4cc74d3a Daniel Axtens 2020-06-03  291  #define __underlying_strcpy	__builtin_strcpy
b008ae4cc74d3a Daniel Axtens 2020-06-03  292  #define __underlying_strlen	__builtin_strlen
b008ae4cc74d3a Daniel Axtens 2020-06-03  293  #define __underlying_strncat	__builtin_strncat
b008ae4cc74d3a Daniel Axtens 2020-06-03 @294  #define __underlying_strncpy	__builtin_strncpy
b008ae4cc74d3a Daniel Axtens 2020-06-03  295  #endif
b008ae4cc74d3a Daniel Axtens 2020-06-03  296  

:::::: The code at line 294 was first introduced by commit
:::::: b008ae4cc74d3ab43074099746f6c32d353e01aa string.h: fix incompatibility between FORTIFY_SOURCE and KASAN

:::::: TO: Daniel Axtens <dja@axtens.net>
:::::: CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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