Hi David,

I love your patch! Yet something to improve:

[auto build test ERROR on cgroup/for-next]
[also build test ERROR on dhowells-fs/fscache-next linus/master v5.11-rc6]
[cannot apply to security/next-testing tip/timers/core next-20210125]
[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/David-Howells/keys-request_key-interception-in-containers/20210205-015946
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next
config: parisc-randconfig-r001-20210204 (attached as .config)
compiler: hppa-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
        # https://github.com/0day-ci/linux/commit/9ec38626d1262923d124035eeb6e2fdaa181b6c4
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review David-Howells/keys-request_key-interception-in-containers/20210205-015946
        git checkout 9ec38626d1262923d124035eeb6e2fdaa181b6c4
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=parisc 

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 >>):

>> hppa-linux-ld: net/core/net_namespace.o:(.data+0x108): undefined reference to `netns_operations'

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