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Date:   Fri, 11 Aug 2023 21:28:13 +0800
From:   kernel test robot <lkp@intel.com>
To:     Li kunyu <kunyu@nfschina.com>, 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 <kunyu@nfschina.com>
Subject: Re: [PATCH] cgroup: cgroup: =?utf-8?Q?Remo?=
 =?utf-8?B?dmUgdW5uZWNlc3Nhcnkg4oCYMOKAmQ==?= values from ret
Message-ID: <202308112139.lVjuXYZg-lkp@intel.com>
References: <20230813014734.2916-1-kunyu@nfschina.com>
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In-Reply-To: <20230813014734.2916-1-kunyu@nfschina.com>
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Hi Li,

kernel test robot noticed the following build warnings:

[auto build test WARNING on v6.5-rc5]
[also build test WARNING on linus/master next-20230809]
[cannot apply to tj-cgroup/for-next]
[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-0-values-from-ret/20230811-171814
base:   v6.5-rc5
patch link:    https://lore.kernel.org/r/20230813014734.2916-1-kunyu%40nfschina.com
patch subject: [PATCH] cgroup: cgroup: Remove unnecessary ‘0’ values from ret
config: x86_64-randconfig-r035-20230811 (https://download.01.org/0day-ci/archive/20230811/202308112139.lVjuXYZg-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/20230811/202308112139.lVjuXYZg-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 <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202308112139.lVjuXYZg-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/cgroup/cgroup.c:7000:56: warning: variable 'ret' is uninitialized when used here [-Wuninitialized]
           ret = show_delegatable_files(cgroup_base_files, buf + ret,
                                                                 ^~~
   kernel/cgroup/cgroup.c:6998:13: note: initialize the variable 'ret' to silence this warning
           ssize_t ret;
                      ^
                       = 0
   1 warning generated.


vim +/ret +7000 kernel/cgroup/cgroup.c

01ee6cfb1483fe Roman Gushchin 2017-11-06  6992  
01ee6cfb1483fe Roman Gushchin 2017-11-06  6993  static ssize_t delegate_show(struct kobject *kobj, struct kobj_attribute *attr,
01ee6cfb1483fe Roman Gushchin 2017-11-06  6994  			      char *buf)
01ee6cfb1483fe Roman Gushchin 2017-11-06  6995  {
01ee6cfb1483fe Roman Gushchin 2017-11-06  6996  	struct cgroup_subsys *ss;
01ee6cfb1483fe Roman Gushchin 2017-11-06  6997  	int ssid;
3d7f13682faf54 Li kunyu       2023-08-13  6998  	ssize_t ret;
01ee6cfb1483fe Roman Gushchin 2017-11-06  6999  
8a693f7766f9e2 Tejun Heo      2022-09-06 @7000  	ret = show_delegatable_files(cgroup_base_files, buf + ret,
8a693f7766f9e2 Tejun Heo      2022-09-06  7001  				     PAGE_SIZE - ret, NULL);
8a693f7766f9e2 Tejun Heo      2022-09-06  7002  	if (cgroup_psi_enabled())
8a693f7766f9e2 Tejun Heo      2022-09-06  7003  		ret += show_delegatable_files(cgroup_psi_files, buf + ret,
8a693f7766f9e2 Tejun Heo      2022-09-06  7004  					      PAGE_SIZE - ret, NULL);
01ee6cfb1483fe Roman Gushchin 2017-11-06  7005  
01ee6cfb1483fe Roman Gushchin 2017-11-06  7006  	for_each_subsys(ss, ssid)
01ee6cfb1483fe Roman Gushchin 2017-11-06  7007  		ret += show_delegatable_files(ss->dfl_cftypes, buf + ret,
01ee6cfb1483fe Roman Gushchin 2017-11-06  7008  					      PAGE_SIZE - ret,
01ee6cfb1483fe Roman Gushchin 2017-11-06  7009  					      cgroup_subsys_name[ssid]);
01ee6cfb1483fe Roman Gushchin 2017-11-06  7010  
01ee6cfb1483fe Roman Gushchin 2017-11-06  7011  	return ret;
01ee6cfb1483fe Roman Gushchin 2017-11-06  7012  }
01ee6cfb1483fe Roman Gushchin 2017-11-06  7013  static struct kobj_attribute cgroup_delegate_attr = __ATTR_RO(delegate);
01ee6cfb1483fe Roman Gushchin 2017-11-06  7014  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki