Hi Alexey,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linux/master]
[also build test WARNING on kees/for-next/pstore linus/master v5.9-rc1 next-20200819]
[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]

url:    https://github.com/0day-ci/linux/commits/Alexey-Gladkov/proc-Relax-check-of-mount-visibility/20200820-031542
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git bcf876870b95592b52519ed4aafcf9d95999bc9c
config: xtensa-allyesconfig (attached as .config)
compiler: xtensa-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=xtensa 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   fs/proc/root.c: In function 'proc_fill_super':
>> fs/proc/root.c:187:24: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     187 |  fs_info->mounter_cred = get_cred(fc->cred);
         |                        ^
   fs/proc/root.c: In function 'proc_reconfigure':
   fs/proc/root.c:229:24: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     229 |  fs_info->mounter_cred = get_cred(fc->cred);
         |                        ^

# https://github.com/0day-ci/linux/commit/9c2a0eea7f38b1a4e201b8f2da0c5fd7b423daf9
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Alexey-Gladkov/proc-Relax-check-of-mount-visibility/20200820-031542
git checkout 9c2a0eea7f38b1a4e201b8f2da0c5fd7b423daf9
vim +/const +187 fs/proc/root.c

   164	
   165	static int proc_fill_super(struct super_block *s, struct fs_context *fc)
   166	{
   167		struct proc_fs_context *ctx = fc->fs_private;
   168		struct inode *root_inode;
   169		struct proc_fs_info *fs_info;
   170		int ret;
   171	
   172		fs_info = kzalloc(sizeof(*fs_info), GFP_KERNEL);
   173		if (!fs_info)
   174			return -ENOMEM;
   175	
   176		/* User space would break if executables or devices appear on proc */
   177		s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
   178		s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
   179		s->s_blocksize = 1024;
   180		s->s_blocksize_bits = 10;
   181		s->s_magic = PROC_SUPER_MAGIC;
   182		s->s_op = &proc_sops;
   183		s->s_time_gran = 1;
   184		s->s_fs_info = fs_info;
   185	
   186		fs_info->pid_ns = get_pid_ns(ctx->pid_ns);
 > 187		fs_info->mounter_cred = get_cred(fc->cred);
   188	
   189		proc_apply_options(s, fc, current_user_ns());
   190	
   191		/*
   192		 * procfs isn't actually a stacking filesystem; however, there is
   193		 * too much magic going on inside it to permit stacking things on
   194		 * top of it
   195		 */
   196		s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
   197	
   198		/* procfs dentries and inodes don't require IO to create */
   199		s->s_shrink.seeks = 0;
   200	
   201		pde_get(&proc_root);
   202		root_inode = proc_get_inode(s, &proc_root);
   203		if (!root_inode) {
   204			pr_err("proc_fill_super: get root inode failed\n");
   205			return -ENOMEM;
   206		}
   207	
   208		s->s_root = d_make_root(root_inode);
   209		if (!s->s_root) {
   210			pr_err("proc_fill_super: allocate dentry failed\n");
   211			return -ENOMEM;
   212		}
   213	
   214		ret = proc_setup_self(s);
   215		if (ret) {
   216			return ret;
   217		}
   218		return proc_setup_thread_self(s);
   219	}
   220	

---
0-DAY CI Kernel Test Service, Intel Corporation
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