From mboxrd@z Thu Jan 1 00:00:00 1970 From: kernel test robot Subject: Re: [PATCH] cgroup: cgroup: =?utf-8?Q?Remo?= =?utf-8?B?dmUgdW5uZWNlc3Nhcnkg4oCYTlVMTOKAmQ==?= values from res Date: Sat, 12 Aug 2023 13:43:51 +0800 Message-ID: <202308121338.k2YdCXVR-lkp@intel.com> References: <20230813015142.3095-1-kunyu@nfschina.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691819047; x=1723355047; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=vsrqajthoEmurm5NVfeEuBVx0HE3ai+cd5EQa9FXyeU=; b=O11TuYHTxBpvqxfQ8kbsaG2f1S3kIjFEidbn/fH7Y7hAGOkLu3RnoX/4 xz0/zl4QFfJ+HwLS/PC4RWRvZZhuUJFpoHmcz2l7nFvgHRQ+WTCjZfYU2 DvaA5U66JMwOXdeVXNDBaUl8FGS7HvdhnkYB6QQ0Q3POIEeWsSjz6RHu7 IHPIou5ptwnppWmPeZWskjxSe90ynhtVySggyfEwIFEZjspqFnpaWse1i 1lqDXv4Z473s2+2xeaC5HZaMvi10Tz1Tzmec7OTYOm7JTFT8/OweMvBVB TaJd4YwHd0eO/4FyEs1dukdp5KSjkasFGk7EbsIEXPeal/zHmoiBv5Dv4 w==; Content-Disposition: inline In-Reply-To: <20230813015142.3095-1-kunyu@nfschina.com> List-ID: Content-Type: text/plain; charset="utf-8" To: Li kunyu , tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Li kunyu 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@intel.com/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@intel.com/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 | Closes: https://lore.kernel.org/oe-kbuild-all/202308121338.k2YdCXVR-lkp@intel.com/ 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