Re: [PATCH v7 13/16] mm: memory: support clearing page ranges

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

Hi Ankur,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Ankur-Arora/perf-bench-mem-Remove-repetition-around-time-measurement/20250917-233045
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250917152418.4077386-14-ankur.a.arora%40oracle.com
patch subject: [PATCH v7 13/16] mm: memory: support clearing page ranges
config: arm-randconfig-001-20250919 (https://download.01.org/0day-ci/archive/20250919/202509191916.a0oRRfua-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 12.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250919/202509191916.a0oRRfua-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/202509191916.a0oRRfua-lkp@intel.com/

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

   In file included from arch/arm/include/asm/thread_info.h:14,
                    from include/linux/thread_info.h:60,
                    from include/asm-generic/preempt.h:5,
                    from ./arch/arm/include/generated/asm/preempt.h:1,
                    from include/linux/preempt.h:79,
                    from include/linux/smp.h:116,
                    from include/linux/kernel_stat.h:5,
                    from mm/memory.c:42:
   mm/memory.c: In function 'clear_contig_highpages':
   mm/memory.c:7199:38: error: implicit declaration of function 'nth_page'; did you mean 'pte_page'? [-Werror=implicit-function-declaration]
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                                      ^~~~~~~~
   arch/arm/include/asm/page.h:152:36: note: in definition of macro 'clear_user_highpage'
     152 |          __cpu_clear_user_highpage(page, vaddr)
         |                                    ^~~~
   mm/memory.c:7199:17: note: in expansion of macro 'clear_user_highpages'
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                 ^~~~~~~~~~~~~~~~~~~~
>> mm/memory.c:7199:38: warning: passing argument 1 of 'cpu_user.cpu_clear_user_highpage' makes pointer from integer without a cast [-Wint-conversion]
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                                      ^~~~~~~~~~~~~~~~~
         |                                      |
         |                                      int
   arch/arm/include/asm/page.h:152:36: note: in definition of macro 'clear_user_highpage'
     152 |          __cpu_clear_user_highpage(page, vaddr)
         |                                    ^~~~
   mm/memory.c:7199:17: note: in expansion of macro 'clear_user_highpages'
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                 ^~~~~~~~~~~~~~~~~~~~
   mm/memory.c:7199:38: note: expected 'struct page *' but argument is of type 'int'
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                                      ^~~~~~~~~~~~~~~~~
   arch/arm/include/asm/page.h:152:36: note: in definition of macro 'clear_user_highpage'
     152 |          __cpu_clear_user_highpage(page, vaddr)
         |                                    ^~~~
   mm/memory.c:7199:17: note: in expansion of macro 'clear_user_highpages'
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                 ^~~~~~~~~~~~~~~~~~~~
>> arch/arm/include/asm/page.h:157:15: error: lvalue required as left operand of assignment
     157 |         vaddr += PAGE_SIZE;                             \
         |               ^~
   mm/memory.c:7199:17: note: in expansion of macro 'clear_user_highpages'
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                 ^~~~~~~~~~~~~~~~~~~~
>> arch/arm/include/asm/page.h:158:13: error: lvalue required as increment operand
     158 |         page++;                                         \
         |             ^~
   mm/memory.c:7199:17: note: in expansion of macro 'clear_user_highpages'
    7199 |                 clear_user_highpages(nth_page(page, i),
         |                 ^~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +7199 mm/memory.c

  7185	
  7186	/*
  7187	 * Clear contiguous pages chunking them up when running under
  7188	 * non-preemptible models.
  7189	 */
  7190	static void clear_contig_highpages(struct page *page, unsigned long addr,
  7191					   unsigned int npages)
  7192	{
  7193		unsigned int i, count, unit;
  7194	
  7195		unit = preempt_model_preemptible() ? npages : PAGE_CONTIG_NR;
  7196	
  7197		for (i = 0; i < npages; ) {
  7198			count = min(unit, npages - i);
> 7199			clear_user_highpages(nth_page(page, i),
  7200					     addr + i * PAGE_SIZE, count);
  7201			i += count;
  7202			cond_resched();
  7203		}
  7204	}
  7205	

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