Re: [PATCH v30 2/6] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs

[kernel test robot]

Hi Muhammad,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on next-20230815]
[cannot apply to linus/master v6.5-rc6]
[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/Muhammad-Usama-Anjum/userfaultfd-UFFD_FEATURE_WP_ASYNC/20230816-150412
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20230816065925.850879-3-usama.anjum%40collabora.com
patch subject: [PATCH v30 2/6] fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20230816/202308161737.upLWpu8Q-lkp@xxxxxxxxx/config)
compiler: m68k-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230816/202308161737.upLWpu8Q-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/202308161737.upLWpu8Q-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

   In file included from include/asm-generic/bug.h:5,
                    from arch/m68k/include/asm/bug.h:32,
                    from include/linux/bug.h:5,
                    from include/linux/mmdebug.h:5,
                    from include/linux/mm.h:6,
                    from include/linux/pagewalk.h:5,
                    from fs/proc/task_mmu.c:2:
   fs/proc/task_mmu.c: In function 'pagemap_scan_get_args':
>> fs/proc/task_mmu.c:2269:24: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    2269 |         if (!access_ok((void __user *)arg->start, arg->end - arg->start))
         |                        ^
   include/linux/compiler.h:76:45: note: in definition of macro 'likely'
      76 | # define likely(x)      __builtin_expect(!!(x), 1)
         |                                             ^
   fs/proc/task_mmu.c:2269:14: note: in expansion of macro 'access_ok'
    2269 |         if (!access_ok((void __user *)arg->start, arg->end - arg->start))
         |              ^~~~~~~~~
   fs/proc/task_mmu.c:2273:36: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    2273 |         if (arg->vec && !access_ok((void __user *)arg->vec,
         |                                    ^
   include/linux/compiler.h:76:45: note: in definition of macro 'likely'
      76 | # define likely(x)      __builtin_expect(!!(x), 1)
         |                                             ^
   fs/proc/task_mmu.c:2273:26: note: in expansion of macro 'access_ok'
    2273 |         if (arg->vec && !access_ok((void __user *)arg->vec,
         |                          ^~~~~~~~~
   fs/proc/task_mmu.c: In function 'pagemap_scan_init_bounce_buffer':
   fs/proc/task_mmu.c:2310:22: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    2310 |         p->vec_out = (struct page_region __user *)p->arg.vec;
         |                      ^
   fs/proc/task_mmu.c: At top level:
   fs/proc/task_mmu.c:1998:13: warning: 'pagemap_scan_backout_range' defined but not used [-Wunused-function]
    1998 | static void pagemap_scan_backout_range(struct pagemap_scan_private *p,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~


vim +2269 fs/proc/task_mmu.c

  2245	
  2246	static int pagemap_scan_get_args(struct pm_scan_arg *arg,
  2247					 unsigned long uarg)
  2248	{
  2249		if (copy_from_user(arg, (void __user *)uarg, sizeof(*arg)))
  2250			return -EFAULT;
  2251	
  2252		if (arg->size != sizeof(struct pm_scan_arg))
  2253			return -EINVAL;
  2254	
  2255		/* Validate requested features */
  2256		if (arg->flags & ~PM_SCAN_FLAGS)
  2257			return -EINVAL;
  2258		if ((arg->category_inverted | arg->category_mask |
  2259		     arg->category_anyof_mask | arg->return_mask) & ~PM_SCAN_CATEGORIES)
  2260			return -EINVAL;
  2261	
  2262		arg->start = untagged_addr((unsigned long)arg->start);
  2263		arg->end = untagged_addr((unsigned long)arg->end);
  2264		arg->vec = untagged_addr((unsigned long)arg->vec);
  2265	
  2266		/* Validate memory pointers */
  2267		if (!IS_ALIGNED(arg->start, PAGE_SIZE))
  2268			return -EINVAL;
> 2269		if (!access_ok((void __user *)arg->start, arg->end - arg->start))
  2270			return -EFAULT;
  2271		if (!arg->vec && arg->vec_len)
  2272			return -EINVAL;
  2273		if (arg->vec && !access_ok((void __user *)arg->vec,
  2274				      arg->vec_len * sizeof(struct page_region)))
  2275			return -EFAULT;
  2276	
  2277		/* Fixup default values */
  2278		arg->end = ALIGN(arg->end, PAGE_SIZE);
  2279		arg->walk_end = 0;
  2280		if (!arg->max_pages)
  2281			arg->max_pages = ULONG_MAX;
  2282	
  2283		return 0;
  2284	}
  2285	

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