Hi Alexey, Thank you for the patch! Yet something to improve: [auto build test ERROR on linux/master] [also build test ERROR 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: s390-randconfig-r034-20200818 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project b34b1e38381fa4d1b1d9751a6b5233b68e734cfe) 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 # install s390 cross compiling tool for clang build # apt-get install binutils-s390x-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): >> fs/proc/root.c:187:24: error: assigning to 'struct cred *' from 'const struct cred *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers] fs_info->mounter_cred = get_cred(fc->cred); ^ ~~~~~~~~~~~~~~~~~~ fs/proc/root.c:229:24: error: assigning to 'struct cred *' from 'const struct cred *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers] fs_info->mounter_cred = get_cred(fc->cred); ^ ~~~~~~~~~~~~~~~~~~ 2 errors generated. # 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 +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 https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org