Hi John, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on rdma/for-next] [also build test WARNING on linus/master v5.5-rc2 next-20191216] [cannot apply to mmotm/master vfio/next] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/John-Hubbard/mm-gup-track-dma-pinned-pages-FOLL_PIN/20191212-013238 base: https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git for-next reproduce: # apt-get install sparse # sparse version: v0.6.1-104-gf934193-dirty make ARCH=x86_64 allmodconfig make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' If you fix the issue, kindly add following tag Reported-by: kbuild test robot <lkp@xxxxxxxxx> sparse warnings: (new ones prefixed by >>) >> mm/gup.c:78:26: sparse: sparse: symbol 'try_pin_compound_head' was not declared. Should it be static? Please review and possibly fold the followup patch. --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx Intel Corporation