Re: [PATCH] /dev/zero: try to align PMD_SIZE for private mapping

[kernel test robot]

Hi Zhang,

kernel test robot noticed the following build errors:

[auto build test ERROR on char-misc/char-misc-testing]
[also build test ERROR on char-misc/char-misc-next char-misc/char-misc-linus soc/for-next linus/master v6.16 next-20250729]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Zhang-Qilong/dev-zero-try-to-align-PMD_SIZE-for-private-mapping/20250729-215253
base:   char-misc/char-misc-testing
patch link:    https://lore.kernel.org/r/20250729134942.900517-1-zhangqilong3%40huawei.com
patch subject: [PATCH] /dev/zero: try to align PMD_SIZE for private mapping
config: alpha-allnoconfig (https://download.01.org/0day-ci/archive/20250730/202507301149.ILLCBOyz-lkp@xxxxxxxxx/config)
compiler: alpha-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250730/202507301149.ILLCBOyz-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507301149.ILLCBOyz-lkp@xxxxxxxxx/

All errors (new ones prefixed by >>):

   In file included from include/uapi/linux/posix_types.h:5,
                    from include/uapi/linux/types.h:14,
                    from include/linux/types.h:6,
                    from include/linux/kasan-checks.h:5,
                    from include/asm-generic/rwonce.h:26,
                    from arch/alpha/include/asm/rwonce.h:33,
                    from include/linux/compiler.h:390,
                    from include/linux/export.h:5,
                    from include/linux/linkage.h:7,
                    from arch/alpha/include/asm/bug.h:5,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/mm.h:6,
                    from drivers/char/mem.c:12:
   drivers/char/mem.c: In function 'get_unmapped_area_zero':
>> include/linux/stddef.h:8:14: error: called object is not a function or function pointer
       8 | #define NULL ((void *)0)
         |              ^
   include/linux/huge_mm.h:536:33: note: in expansion of macro 'NULL'
     536 | #define thp_get_unmapped_area   NULL
         |                                 ^~~~
   drivers/char/mem.c:533:15: note: in expansion of macro 'thp_get_unmapped_area'
     533 |         ret = thp_get_unmapped_area(file, addr, len, pgoff, flags);
         |               ^~~~~~~~~~~~~~~~~~~~~


vim +8 include/linux/stddef.h

^1da177e4c3f41 Linus Torvalds   2005-04-16  6  
^1da177e4c3f41 Linus Torvalds   2005-04-16  7  #undef NULL
^1da177e4c3f41 Linus Torvalds   2005-04-16 @8  #define NULL ((void *)0)
6e218287432472 Richard Knutsson 2006-09-30  9  

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