Hi Zi,

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.12-rc2 next-20170525]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Zi-Yan/mm-page-migration-enhancement-for-thp/20170526-003749
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: i386-randconfig-x016-201721 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All error/warnings (new ones prefixed by >>):

   In file included from fs//proc/task_mmu.c:15:0:
   include/linux/swapops.h: In function 'swp_entry_to_pmd':
   include/linux/swapops.h:222:16: warning: missing braces around initializer [-Wmissing-braces]
     return (pmd_t){{ 0 }};
                   ^
   include/linux/swapops.h:222:16: note: (near initialization for '(anonymous)')
   In file included from include/asm-generic/bug.h:4:0,
                    from arch/x86/include/asm/bug.h:81,
                    from include/linux/bug.h:4,
                    from include/linux/mmdebug.h:4,
                    from include/linux/mm.h:8,
                    from fs//proc/task_mmu.c:1:
   In function 'pmd_to_swp_entry.isra.34',
       inlined from 'pagemap_pmd_range' at fs//proc/task_mmu.c:1242:16:
>> include/linux/compiler.h:525:38: error: call to '__compiletime_assert_215' declared with attribute error: BUILD_BUG failed
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
                                         ^
   include/linux/compiler.h:508:4: note: in definition of macro '__compiletime_assert'
       prefix ## suffix();    \
       ^~~~~~
   include/linux/compiler.h:525:2: note: in expansion of macro '_compiletime_assert'
     _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
     ^~~~~~~~~~~~~~~~~~~
   include/linux/bug.h:54:37: note: in expansion of macro 'compiletime_assert'
    #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                        ^~~~~~~~~~~~~~~~~~
   include/linux/bug.h:88:21: note: in expansion of macro 'BUILD_BUG_ON_MSG'
    #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
                        ^~~~~~~~~~~~~~~~
>> include/linux/swapops.h:215:2: note: in expansion of macro 'BUILD_BUG'
     BUILD_BUG();
     ^~~~~~~~~

vim +/BUILD_BUG +215 include/linux/swapops.h

2182e56bf Zi Yan 2017-05-25  199  static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
2182e56bf Zi Yan 2017-05-25  200  		struct page *page)
2182e56bf Zi Yan 2017-05-25  201  {
2182e56bf Zi Yan 2017-05-25  202  	BUILD_BUG();
2182e56bf Zi Yan 2017-05-25  203  }
2182e56bf Zi Yan 2017-05-25  204  
2182e56bf Zi Yan 2017-05-25  205  static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
2182e56bf Zi Yan 2017-05-25  206  		struct page *new)
2182e56bf Zi Yan 2017-05-25  207  {
2182e56bf Zi Yan 2017-05-25  208  	BUILD_BUG();
2182e56bf Zi Yan 2017-05-25  209  }
2182e56bf Zi Yan 2017-05-25  210  
2182e56bf Zi Yan 2017-05-25  211  static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
2182e56bf Zi Yan 2017-05-25  212  
2182e56bf Zi Yan 2017-05-25  213  static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
2182e56bf Zi Yan 2017-05-25  214  {
2182e56bf Zi Yan 2017-05-25 @215  	BUILD_BUG();
2182e56bf Zi Yan 2017-05-25  216  	return swp_entry(0, 0);
2182e56bf Zi Yan 2017-05-25  217  }
2182e56bf Zi Yan 2017-05-25  218  
2182e56bf Zi Yan 2017-05-25  219  static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
2182e56bf Zi Yan 2017-05-25  220  {
2182e56bf Zi Yan 2017-05-25  221  	BUILD_BUG();
2182e56bf Zi Yan 2017-05-25  222  	return (pmd_t){{ 0 }};
2182e56bf Zi Yan 2017-05-25  223  }

:::::: The code at line 215 was first introduced by commit
:::::: 2182e56bfe80b55d1a9a8e8de04e6a5578b1dce0 mm: thp: enable thp migration in generic path

:::::: TO: Zi Yan <zi.yan@cs.rutgers.edu>
:::::: CC: 0day robot <fengguang.wu@intel.com>

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