tree: https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git 20211116-sysctl-cleanups-v4 head: 5347239461f25fc50aa761923245b9ec4a4aafec commit: e854631643628749ab037f54ca9c26d69ffabb3e [3/35] hung_task: Move hung_task sysctl interface to hung_task.c config: i386-randconfig-s002-20211117 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.4-dirty # https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git/com... git remote add mcgrof-next https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git git fetch --no-tags mcgrof-next 20211116-sysctl-cleanups-v4 git checkout e854631643628749ab037f54ca9c26d69ffabb3e # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=i386 SHELL=/bin/bash 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 >>) kernel/hung_task.c:31:19: sparse: sparse: symbol 'sysctl_hung_task_check_count' was not declared. Should it be static? kernel/hung_task.c:50:29: sparse: sparse: symbol 'sysctl_hung_task_check_interval_secs' was not declared. Should it be static? kernel/hung_task.c:52:19: sparse: sparse: symbol 'sysctl_hung_task_warnings' was not declared. Should it be static? kernel/hung_task.c:76:28: sparse: sparse: symbol 'sysctl_hung_task_panic' was not declared. Should it be static? kernel/hung_task.c:282:52: sparse: expected void * kernel/hung_task.c:282:52: sparse: got void [noderef] __user *buffer kernel/hung_task.c:332:35: sparse: expected int ( [usertype] *proc_handler )( ... ) kernel/hung_task.c:332:35: sparse: got int ( * )( ... ) kernel/hung_task.c:340:35: sparse: sparse: incorrect type in initializer (incompatible argument 3 (different address spaces)) @@ expected int ( [usertype] *proc_handler )( ... ) @@ got int ( * )( ... ) @@ kernel/hung_task.c:340:35: sparse: expected int ( [usertype] *proc_handler )( ... ) kernel/hung_task.c:340:35: sparse: got int ( * )( ... ) 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