Hi Li, kernel test robot noticed the following build warnings: [auto build test WARNING on tj-cgroup/for-next] [cannot apply to linus/master v6.5-rc5 next-20230809] [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#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Li-kunyu/cgroup-cgroup-Remove-unnecessary-NULL-values-from-res/20230811-172322 base: https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next patch link: https://lore.kernel.org/r/20230813015142.3095-1-kunyu%40nfschina.com patch subject: [PATCH] cgroup: cgroup: Remove unnecessary ‘NULL’ values from res config: x86_64-randconfig-x002-20230812 (https://download.01.org/0day-ci/archive/20230812/202308121338.k2YdCXVR-lkp@xxxxxxxxx/config) compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07) reproduce: (https://download.01.org/0day-ci/archive/20230812/202308121338.k2YdCXVR-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202308121338.k2YdCXVR-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> kernel/cgroup/cgroup.c:1380:3: warning: variable 'res' is used uninitialized whenever 'for' loop exits because its condition is false [-Wsometimes-uninitialized] list_for_each_entry(link, &cset->cgrp_links, cgrp_link) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/list.h:578:7: note: expanded from macro 'list_for_each_entry' &pos->member != (head); \ ^~~~~~~~~~~~~~~~~~~~~~ kernel/cgroup/cgroup.c:1391:10: note: uninitialized use occurs here BUG_ON(!res); ^~~ include/asm-generic/bug.h:62:45: note: expanded from macro 'BUG_ON' #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0) ^~~~~~~~~ include/linux/compiler.h:78:42: note: expanded from macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ kernel/cgroup/cgroup.c:1380:3: note: remove the condition if it is always true list_for_each_entry(link, &cset->cgrp_links, cgrp_link) { ^ include/linux/list.h:578:7: note: expanded from macro 'list_for_each_entry' &pos->member != (head); \ ^ kernel/cgroup/cgroup.c:1367:20: note: initialize the variable 'res' to silence this warning struct cgroup *res; ^ = NULL 1 warning generated. vim +1380 kernel/cgroup/cgroup.c f2e85d574e881f kernel/cgroup.c Tejun Heo 2014-02-11 1359 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1360 /* 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1361 * look up cgroup associated with current task's cgroup namespace on the 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1362 * specified hierarchy 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1363 */ 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1364 static struct cgroup * 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1365 current_cgns_cgroup_from_root(struct cgroup_root *root) 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1366 { aa6f66ec5ebc27 kernel/cgroup/cgroup.c Li kunyu 2023-08-13 1367 struct cgroup *res; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1368 struct css_set *cset; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1369 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1370 lockdep_assert_held(&css_set_lock); 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1371 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1372 rcu_read_lock(); 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1373 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1374 cset = current->nsproxy->cgroup_ns->root_cset; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1375 if (cset == &init_css_set) { 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1376 res = &root->cgrp; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1377 } else { 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1378 struct cgrp_cset_link *link; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1379 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 @1380 list_for_each_entry(link, &cset->cgrp_links, cgrp_link) { 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1381 struct cgroup *c = link->cgrp; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1382 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1383 if (c->root == root) { 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1384 res = c; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1385 break; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1386 } 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1387 } 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1388 } 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1389 rcu_read_unlock(); 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1390 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1391 BUG_ON(!res); 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1392 return res; 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1393 } 4f41fc59620fce kernel/cgroup.c Serge E. Hallyn 2016-05-09 1394 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
