Re: [PATCH v2 3/7] mm: Add batched versions of ptep_modify_prot_start/commit

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

Hi Dev,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on arm64/for-next/core linus/master v6.15-rc4 next-20250429]
[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/Dev-Jain/mm-Refactor-code-in-mprotect/20250429-133151
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250429052336.18912-4-dev.jain%40arm.com
patch subject: [PATCH v2 3/7] mm: Add batched versions of ptep_modify_prot_start/commit
config: arm-randconfig-001-20250430 (https://download.01.org/0day-ci/archive/20250430/202504301319.aph2eccP-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250430/202504301319.aph2eccP-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/202504301319.aph2eccP-lkp@intel.com/

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

   In file included from include/linux/mm.h:31,
                    from arch/arm/kernel/asm-offsets.c:12:
   include/linux/pgtable.h: In function 'modify_prot_start_ptes':
   include/linux/pgtable.h:901:8: error: implicit declaration of function 'ptep_modify_prot_start' [-Werror=implicit-function-declaration]
     901 |  pte = ptep_modify_prot_start(vma, addr, ptep);
         |        ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/pgtable.h: In function 'modify_prot_commit_ptes':
   include/linux/pgtable.h:921:3: error: implicit declaration of function 'ptep_modify_prot_commit' [-Werror=implicit-function-declaration]
     921 |   ptep_modify_prot_commit(vma, addr, ptep, old_pte, pte);
         |   ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/pgtable.h: At top level:
>> include/linux/pgtable.h:1356:21: error: conflicting types for 'ptep_modify_prot_start'
    1356 | static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
         |                     ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/pgtable.h:901:8: note: previous implicit declaration of 'ptep_modify_prot_start' was here
     901 |  pte = ptep_modify_prot_start(vma, addr, ptep);
         |        ^~~~~~~~~~~~~~~~~~~~~~
>> include/linux/pgtable.h:1367:20: warning: conflicting types for 'ptep_modify_prot_commit'
    1367 | static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
         |                    ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/pgtable.h:1367:20: error: static declaration of 'ptep_modify_prot_commit' follows non-static declaration
   include/linux/pgtable.h:921:3: note: previous implicit declaration of 'ptep_modify_prot_commit' was here
     921 |   ptep_modify_prot_commit(vma, addr, ptep, old_pte, pte);
         |   ^~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors
   make[3]: *** [scripts/Makefile.build:98: arch/arm/kernel/asm-offsets.s] Error 1 shuffle=2044487564
   make[3]: Target 'prepare' not remade because of errors.
   make[2]: *** [Makefile:1280: prepare0] Error 2 shuffle=2044487564
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:248: __sub-make] Error 2 shuffle=2044487564
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:248: __sub-make] Error 2 shuffle=2044487564
   make: Target 'prepare' not remade because of errors.


vim +/ptep_modify_prot_start +1356 include/linux/pgtable.h

1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1340  
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1341  #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1342  /*
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1343   * Start a pte protection read-modify-write transaction, which
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1344   * protects against asynchronous hardware modifications to the pte.
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1345   * The intention is not to prevent the hardware from making pte
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1346   * updates, but to prevent any updates it may make from being lost.
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1347   *
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1348   * This does not protect against other software modifications of the
2eb70aab25dd9b include/linux/pgtable.h       Bhaskar Chowdhury   2021-05-06  1349   * pte; the appropriate pte lock must be held over the transaction.
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1350   *
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1351   * Note that this interface is intended to be batchable, meaning that
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1352   * ptep_modify_prot_commit may not actually update the pte, but merely
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1353   * queue the update to be done at some later time.  The update must be
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1354   * actually committed before the pte lock is released, however.
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1355   */
0cbe3e26abe0cf include/asm-generic/pgtable.h Aneesh Kumar K.V    2019-03-05 @1356  static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma,
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1357  					   unsigned long addr,
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1358  					   pte_t *ptep)
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1359  {
0cbe3e26abe0cf include/asm-generic/pgtable.h Aneesh Kumar K.V    2019-03-05  1360  	return __ptep_modify_prot_start(vma, addr, ptep);
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1361  }
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1362  
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1363  /*
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1364   * Commit an update to a pte, leaving any hardware-controlled bits in
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1365   * the PTE unmodified.
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1366   */
0cbe3e26abe0cf include/asm-generic/pgtable.h Aneesh Kumar K.V    2019-03-05 @1367  static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1368  					   unsigned long addr,
04a8645304500b include/asm-generic/pgtable.h Aneesh Kumar K.V    2019-03-05  1369  					   pte_t *ptep, pte_t old_pte, pte_t pte)
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1370  {
0cbe3e26abe0cf include/asm-generic/pgtable.h Aneesh Kumar K.V    2019-03-05  1371  	__ptep_modify_prot_commit(vma, addr, ptep, pte);
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1372  }
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1373  #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
fe1a6875fcaaac include/asm-generic/pgtable.h Sebastian Siewior   2008-07-15  1374  #endif /* CONFIG_MMU */
1ea0704e0da65b include/asm-generic/pgtable.h Jeremy Fitzhardinge 2008-06-16  1375  

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