Re: [PATCH] prctl: Get private anonymous memory region name

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

Hi Rong,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master v6.7-rc2 next-20231124]
[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/Rong-Tao/prctl-Get-private-anonymous-memory-region-name/20231125-220925
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/tencent_977CBF8E8CA6234A1B740A35655D5D7EAA0A%40qq.com
patch subject: [PATCH] prctl: Get private anonymous memory region name
config: x86_64-randconfig-122-20231126 (https://download.01.org/0day-ci/archive/20231126/202311260535.WXAlmfsl-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231126/202311260535.WXAlmfsl-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/202311260535.WXAlmfsl-lkp@intel.com/

All errors (new ones prefixed by >>):

   kernel/sys.c: In function 'prctl_get_vma':
>> kernel/sys.c:2371:3: error: a label can only be part of a statement and a declaration is not a statement
    2371 |   const struct anon_vma_name *anon_name = NULL;
         |   ^~~~~
   kernel/sys.c:2389:21: warning: passing argument 1 of 'anon_vma_name_put' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
    2389 |   anon_vma_name_put(anon_name);
         |                     ^~~~~~~~~
   In file included from kernel/sys.c:10:
   include/linux/mm_inline.h:363:60: note: expected 'struct anon_vma_name *' but argument is of type 'const struct anon_vma_name *'
     363 | static inline void anon_vma_name_put(struct anon_vma_name *anon_name)
         |                                      ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~


vim +2371 kernel/sys.c

  2361	
  2362	static int prctl_get_vma(unsigned long opt, unsigned long addr,
  2363				 unsigned long buf, unsigned long arg)
  2364	{
  2365		struct mm_struct *mm = current->mm;
  2366		const char __user *u_buf;
  2367		int error;
  2368	
  2369		switch (opt) {
  2370		case PR_GET_VMA_ANON_NAME:
> 2371			const struct anon_vma_name *anon_name = NULL;
  2372	
  2373			u_buf = (const char __user *)buf;
  2374			error = 0;
  2375	
  2376			mmap_read_lock(mm);
  2377			anon_name = madvise_get_anon_name(mm, addr);
  2378			if (!anon_name) {
  2379				mmap_read_unlock(mm);
  2380				error = -EFAULT;
  2381				break;
  2382			}
  2383	
  2384			if (copy_to_user((char __user *)u_buf, anon_name->name,
  2385					 strlen(anon_name->name) + 1))
  2386				error = -EFAULT;
  2387	
  2388			mmap_read_unlock(mm);
  2389			anon_vma_name_put(anon_name);
  2390			break;
  2391		default:
  2392			error = -EINVAL;
  2393		}
  2394		return error;
  2395	}
  2396	

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