[linux-next:master 7021/9870] include/linux/kasan-checks.h:38:27: warning: 'args' may be used uninitialized

[linux-next:master 7021/9870] include/linux/kasan-checks.h:38:27: warning: 'args' may be used uninitialized

[kernel test robot]

:::::: 
:::::: Manual check reason: "likely FALSE maybe-used-uninitialized warning on old compiler"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Mark Harmstone <mark@harmstone.com>
CC: David Sterba <dsterba@suse.com>
CC: Qu Wenruo <wqu@suse.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   7da7f07112610a520567421dd2ffcb51beaefbcc
commit: 3af8c1874c4203ff8a960333e871df58255e6c37 [7021/9870] btrfs: add ioctl GET_CSUMS to read raw checksums from file range
:::::: branch date: 2 days ago
:::::: commit date: 8 days ago
config: arm64-randconfig-004-20260601 (https://download.01.org/0day-ci/archive/20260601/202606011125.SbcePutL-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 14.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260601/202606011125.SbcePutL-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/r/202606011125.SbcePutL-lkp@intel.com/

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   In file included from include/asm-generic/rwonce.h:26,
                    from arch/arm64/include/asm/rwonce.h:81,
                    from include/linux/compiler.h:369,
                    from include/linux/array_size.h:5,
                    from include/linux/kernel.h:16,
                    from fs/btrfs/ioctl.c:6:
   In function 'instrument_copy_from_user_before',
       inlined from '_inline_copy_from_user' at include/linux/uaccess.h:184:2,
       inlined from 'copy_from_user' at include/linux/uaccess.h:221:9,
       inlined from 'btrfs_ioctl_get_csums.isra' at fs/btrfs/ioctl.c:5140:6:
>> include/linux/kasan-checks.h:38:27: warning: 'args' may be used uninitialized [-Wmaybe-uninitialized]
      38 | #define kasan_check_write __kasan_check_write
   include/linux/instrumented.h:146:9: note: in expansion of macro 'kasan_check_write'
     146 |         kasan_check_write(to, n);
         |         ^~~~~~~~~~~~~~~~~
   include/linux/kasan-checks.h: In function 'btrfs_ioctl_get_csums.isra':
   include/linux/kasan-checks.h:20:6: note: by argument 1 of type 'const volatile void *' to '__kasan_check_write' declared here
      20 | bool __kasan_check_write(const volatile void *p, unsigned int size);
         |      ^~~~~~~~~~~~~~~~~~~
   fs/btrfs/ioctl.c:5121:43: note: 'args' declared here
    5121 |         struct btrfs_ioctl_get_csums_args args;
         |                                           ^~~~


vim +/args +38 include/linux/kasan-checks.h

7d8ad890dad00f6 Marco Elver     2019-07-11  31  
7d8ad890dad00f6 Marco Elver     2019-07-11  32  /*
7d8ad890dad00f6 Marco Elver     2019-07-11  33   * kasan_check_*: Only available when the particular compilation unit has KASAN
7d8ad890dad00f6 Marco Elver     2019-07-11  34   * instrumentation enabled. May be used in header files.
7d8ad890dad00f6 Marco Elver     2019-07-11  35   */
7d8ad890dad00f6 Marco Elver     2019-07-11  36  #ifdef __SANITIZE_ADDRESS__
7d8ad890dad00f6 Marco Elver     2019-07-11  37  #define kasan_check_read __kasan_check_read
7d8ad890dad00f6 Marco Elver     2019-07-11 @38  #define kasan_check_write __kasan_check_write
64f8ebaf115bcdd Andrey Ryabinin 2016-05-20  39  #else
b5f6e0fc7d60e02 Marco Elver     2019-07-11  40  static inline bool kasan_check_read(const volatile void *p, unsigned int size)
b5f6e0fc7d60e02 Marco Elver     2019-07-11  41  {
b5f6e0fc7d60e02 Marco Elver     2019-07-11  42  	return true;
b5f6e0fc7d60e02 Marco Elver     2019-07-11  43  }
b5f6e0fc7d60e02 Marco Elver     2019-07-11  44  static inline bool kasan_check_write(const volatile void *p, unsigned int size)
b5f6e0fc7d60e02 Marco Elver     2019-07-11  45  {
b5f6e0fc7d60e02 Marco Elver     2019-07-11  46  	return true;
b5f6e0fc7d60e02 Marco Elver     2019-07-11  47  }
64f8ebaf115bcdd Andrey Ryabinin 2016-05-20  48  #endif
64f8ebaf115bcdd Andrey Ryabinin 2016-05-20  49  

:::::: The code at line 38 was first introduced by commit
:::::: 7d8ad890dad00f6cd64bfb44d9be4fceb10cf819 mm/kasan: introduce __kasan_check_{read,write}

:::::: TO: Marco Elver <elver@google.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>

--
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https://github.com/intel/lkp-tests/wiki