[akpm-mm:mm-unstable 273/420] mm/userfaultfd.c:4475:1: warning: alias and aliasee have different types 'long (int)' and 'long (typeof (__builtin_choose_expr((__builtin_types_compatible_p(typeof ((int)0), typeof (0LL)) || __builtin_types_compatible_p(typeof ((int)0), typeof (0ULL))), 0...

[akpm-mm:mm-unstable 273/420] mm/userfaultfd.c:4475:1: warning: alias and aliasee have different types 'long (int)' and 'long (typeof (__builtin_choose_expr((__builtin_types_compatible_p(typeof ((int)0), typeof (0LL)) || __builtin_types_compatible_p(typeof ((int)0), typeof (0ULL))), 0...

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
head:   8a74e22643189e0ae339afc91110ddb4cab1941b
commit: 688eee218159283140c8c4b48429cfe400cb64e4 [273/420] userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c
config: arm-randconfig-003-20260528 (https://download.01.org/0day-ci/archive/20260528/202605282311.BlbuvsRF-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 9409c07de6378507397ecdb6f05f628f58110112)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260528/202605282311.BlbuvsRF-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/202605282311.BlbuvsRF-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/userfaultfd.c:4475:1: warning: alias and aliasee have different types 'long (int)' and 'long (typeof (__builtin_choose_expr((__builtin_types_compatible_p(typeof ((int)0), typeof (0LL)) || __builtin_types_compatible_p(typeof ((int)0), typeof (0ULL))), 0LL, 0L)))' (aka 'long (long)') [-Wattribute-alias]
    4475 | SYSCALL_DEFINE1(userfaultfd, int, flags)
         | ^
   include/linux/syscalls.h:225:36: note: expanded from macro 'SYSCALL_DEFINE1'
     225 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
         |                                    ^
   include/linux/syscalls.h:236:2: note: expanded from macro 'SYSCALL_DEFINEx'
     236 |         __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
         |         ^
   include/linux/syscalls.h:251:18: note: expanded from macro '__SYSCALL_DEFINEx'
     251 |                 __attribute__((alias(__stringify(__se_sys##name))));    \
         |                                ^
   mm/userfaultfd.c:4475:1: note: aliasee is declared here
   include/linux/syscalls.h:225:36: note: expanded from macro 'SYSCALL_DEFINE1'
     225 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
         |                                    ^
   include/linux/syscalls.h:236:2: note: expanded from macro 'SYSCALL_DEFINEx'
     236 |         __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
         |         ^
   include/linux/syscalls.h:255:18: note: expanded from macro '__SYSCALL_DEFINEx'
     255 |         asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))  \
         |                         ^
   <scratch space>:46:1: note: expanded from here
      46 | __se_sys_userfaultfd
         | ^
   1 warning generated.


vim +4475 mm/userfaultfd.c

  4474	
> 4475	SYSCALL_DEFINE1(userfaultfd, int, flags)
  4476	{
  4477		if (!userfaultfd_syscall_allowed(flags))
  4478			return -EPERM;
  4479	
  4480		return new_userfaultfd(flags);
  4481	}
  4482	

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [akpm-mm:mm-unstable 273/420] mm/userfaultfd.c:4475:1: warning: alias and aliasee have different types 'long (int)' and 'long (typeof (__builtin_choose_expr((__builtin_types_compatible_p(typeof ((int)0), typeof (0LL)) || __builtin_types_compatible_p(typeof ((int)0), typeof (0ULL))), 0...

[Nathan Chancellor]

On Thu, May 28, 2026 at 11:28:25PM +0800, kernel test robot wrote:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
> head:   8a74e22643189e0ae339afc91110ddb4cab1941b
> commit: 688eee218159283140c8c4b48429cfe400cb64e4 [273/420] userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c
> config: arm-randconfig-003-20260528 (https://download.01.org/0day-ci/archive/20260528/202605282311.BlbuvsRF-lkp@intel.com/config)
> compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 9409c07de6378507397ecdb6f05f628f58110112)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260528/202605282311.BlbuvsRF-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/202605282311.BlbuvsRF-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
> >> mm/userfaultfd.c:4475:1: warning: alias and aliasee have different types 'long (int)' and 'long (typeof (__builtin_choose_expr((__builtin_types_compatible_p(typeof ((int)0), typeof (0LL)) || __builtin_types_compatible_p(typeof ((int)0), typeof (0ULL))), 0LL, 0L)))' (aka 'long (long)') [-Wattribute-alias]
>     4475 | SYSCALL_DEFINE1(userfaultfd, int, flags)
>          | ^
>    include/linux/syscalls.h:225:36: note: expanded from macro 'SYSCALL_DEFINE1'
>      225 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
>          |                                    ^
>    include/linux/syscalls.h:236:2: note: expanded from macro 'SYSCALL_DEFINEx'
>      236 |         __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
>          |         ^
>    include/linux/syscalls.h:251:18: note: expanded from macro '__SYSCALL_DEFINEx'
>      251 |                 __attribute__((alias(__stringify(__se_sys##name))));    \
>          |                                ^
>    mm/userfaultfd.c:4475:1: note: aliasee is declared here
>    include/linux/syscalls.h:225:36: note: expanded from macro 'SYSCALL_DEFINE1'
>      225 | #define SYSCALL_DEFINE1(name, ...) SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
>          |                                    ^
>    include/linux/syscalls.h:236:2: note: expanded from macro 'SYSCALL_DEFINEx'
>      236 |         __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
>          |         ^
>    include/linux/syscalls.h:255:18: note: expanded from macro '__SYSCALL_DEFINEx'
>      255 |         asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__))  \
>          |                         ^
>    <scratch space>:46:1: note: expanded from here
>       46 | __se_sys_userfaultfd
>          | ^
>    1 warning generated.

Sorry for the noise, this is from a compiler upgrade, not a fault of
the blamed patch. I plan to submit a fix for this to Linus soon:

  https://git.kernel.org/nathan/c/175db11786bde9061db526bf1ac5107d915f5163

-- 
Cheers,
Nathan