Hi Michal,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on hnaz-mm/master]
[also build test ERROR on linux/master linus/master v5.15-rc1 next-20210916]
[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/Michal-Clapinski/ipc-check-checkpoint_restore_ns_capable-to-modify-C-R-proc-files/20210917-020956
base:   https://github.com/hnaz/linux-mm master
config: microblaze-randconfig-r011-20210916 (attached as .config)
compiler: microblaze-linux-gcc (GCC) 11.2.0
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
        # https://github.com/0day-ci/linux/commit/a667ba4d29dc378f8692185740d1e016832ca20a
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Michal-Clapinski/ipc-check-checkpoint_restore_ns_capable-to-modify-C-R-proc-files/20210917-020956
        git checkout a667ba4d29dc378f8692185740d1e016832ca20a
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=microblaze 

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

All errors (new ones prefixed by >>):

   In file included from include/linux/kernel.h:11,
                    from include/linux/list.h:9,
                    from include/linux/module.h:12,
                    from ipc/ipc_sysctl.c:8:
   ipc/ipc_sysctl.c: In function 'proc_ipc_dointvec_minmax_checkpoint_restore':
>> ipc/ipc_sysctl.c:113:23: error: implicit declaration of function 'checkpoint_restore_ns_capable' [-Werror=implicit-function-declaration]
     113 |         if (write && !checkpoint_restore_ns_capable(user_ns))
         |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var'
      58 | #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
         |                                                    ^~~~
   ipc/ipc_sysctl.c:113:9: note: in expansion of macro 'if'
     113 |         if (write && !checkpoint_restore_ns_capable(user_ns))
         |         ^~
   cc1: some warnings being treated as errors


vim +/checkpoint_restore_ns_capable +113 ipc/ipc_sysctl.c

   106	
   107	#ifdef CONFIG_CHECKPOINT_RESTORE
   108	static int proc_ipc_dointvec_minmax_checkpoint_restore(struct ctl_table *table,
   109			int write, void *buffer, size_t *lenp, loff_t *ppos)
   110	{
   111		struct user_namespace *user_ns = current->nsproxy->ipc_ns->user_ns;
   112	
 > 113		if (write && !checkpoint_restore_ns_capable(user_ns))
   114			return -EPERM;
   115	
   116		return proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
   117	}
   118	#endif
   119	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org