Re: [PATCH v2 2/2] Show /proc/self/net only for CAP_NET_ADMIN

From: kernel test robot
Date: Wed Aug 19 2020 - 19:28:04 EST


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 <lkp@xxxxxxxxx>

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@xxxxxxxxxxxx

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