Hi Taehee, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on net-next/master] url: https://github.com/0day-ci/linux/commits/Taehee-Yoo/mld-change-context-fr... base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 6626a0266566c5aea16178c5e6cd7fc4db3f2f56 config: i386-randconfig-s002-20210209 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.3-215-g0fb77bb6-dirty # https://github.com/0day-ci/linux/commit/9ac7d23c98251efc265073a0d63930c91... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Taehee-Yoo/mld-change-context-from-atomic-to-sleepable/20210209-072339 git checkout 9ac7d23c98251efc265073a0d63930c91739cc02 # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; "sparse warnings: (new ones prefixed by >>)" net/ipv6/mcast.c: note: in included file: include/net/mld.h:32:43: sparse: sparse: array of flexible structures Please review and possibly fold the followup patch. --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org