From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0607DCCA473 for ; Thu, 2 Jun 2022 01:53:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232946AbiFBBxh (ORCPT ); Wed, 1 Jun 2022 21:53:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232944AbiFBBxh (ORCPT ); Wed, 1 Jun 2022 21:53:37 -0400 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D973A25F424; Wed, 1 Jun 2022 18:53:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1654134815; x=1685670815; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=1IXtlOaSA6Lu6LSh/sdcVQX9N0TOTnw/7092N1Jsl5w=; b=TTPGjlPwYmglc/HPqBf9VLuxiYqirQVNZQ4ijqUKvN47ni5YkCuWllcC anty21jwipDrQZmM8l7ysFBVb8XzuCZt0RiR3tcVYr/vZiTDO5cOMfv9+ pSUVxPDkShqxLRfMKu+Elv9Ibuh+wgxbF3m6RzVLLsQv0WxuJzncVHaFz M2mPL2XP3muez1087FtlKHJQ4mZzDkqBOAdNASnyNJKXB2IxhKsEfAg5Z pFdSfcODha/4Z060P7XFP3hWOlmYMuH8WPqot8S3MHJhUCr5hbxplBLYB SdVKdDu0/2rEW0mM4V94JnPpoN5dKhNmi65yW18K8K6QAih3l3DI2GjcV g==; X-IronPort-AV: E=McAfee;i="6400,9594,10365"; a="301151013" X-IronPort-AV: E=Sophos;i="5.91,270,1647327600"; d="scan'208";a="301151013" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2022 18:53:35 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,270,1647327600"; d="scan'208";a="581855082" Received: from lkp-server01.sh.intel.com (HELO 60dabacc1df6) ([10.239.97.150]) by fmsmga007.fm.intel.com with ESMTP; 01 Jun 2022 18:53:33 -0700 Received: from kbuild by 60dabacc1df6 with local (Exim 4.95) (envelope-from ) id 1nwa1k-0004dd-S6; Thu, 02 Jun 2022 01:53:32 +0000 Date: Thu, 2 Jun 2022 09:52:55 +0800 From: kernel test robot To: Waiman Long , Tejun Heo , Jens Axboe Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Ming Lei , Waiman Long Subject: Re: [PATCH v2 2/2] blk-cgroup: Optimize blkcg_rstat_flush() Message-ID: <202206020948.yBhTYYDS-lkp@intel.com> References: <20220601165324.60892-2-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220601165324.60892-2-longman@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Waiman, I love your patch! Perhaps something to improve: [auto build test WARNING on axboe-block/for-next] [also build test WARNING on linus/master next-20220601] [cannot apply to v5.18] [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] url: https://github.com/intel-lab-lkp/linux/commits/Waiman-Long/blk-cgroup-Correctly-free-percpu-iostat_cpu-in-blkg-on-error-exit/20220602-005557 base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next config: x86_64-randconfig-a005 (https://download.01.org/0day-ci/archive/20220602/202206020948.yBhTYYDS-lkp@intel.com/config) compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project c825abd6b0198fb088d9752f556a70705bc99dfd) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/7f5ef1493e681454e71c11b2547638b94665a78f git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Waiman-Long/blk-cgroup-Correctly-free-percpu-iostat_cpu-in-blkg-on-error-exit/20220602-005557 git checkout 7f5ef1493e681454e71c11b2547638b94665a78f # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> block/blk-cgroup.c:1239:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized] if (!blkcg->lhead) ^~~~~~~~~~~~~ block/blk-cgroup.c:1290:9: note: uninitialized use occurs here return ret; ^~~ block/blk-cgroup.c:1239:2: note: remove the 'if' if its condition is always false if (!blkcg->lhead) ^~~~~~~~~~~~~~~~~~ block/blk-cgroup.c:1223:33: note: initialize the variable 'ret' to silence this warning struct cgroup_subsys_state *ret; ^ = NULL 1 warning generated. vim +1239 block/blk-cgroup.c 1218 1219 static struct cgroup_subsys_state * 1220 blkcg_css_alloc(struct cgroup_subsys_state *parent_css) 1221 { 1222 struct blkcg *blkcg; 1223 struct cgroup_subsys_state *ret; 1224 int i; 1225 1226 mutex_lock(&blkcg_pol_mutex); 1227 1228 if (!parent_css) { 1229 blkcg = &blkcg_root; 1230 } else { 1231 blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL); 1232 if (!blkcg) { 1233 ret = ERR_PTR(-ENOMEM); 1234 goto unlock; 1235 } 1236 } 1237 1238 blkcg->lhead = alloc_percpu_gfp(struct llist_head, GFP_KERNEL); > 1239 if (!blkcg->lhead) 1240 goto free_blkcg; 1241 init_blkcg_llists(blkcg); 1242 1243 for (i = 0; i < BLKCG_MAX_POLS ; i++) { 1244 struct blkcg_policy *pol = blkcg_policy[i]; 1245 struct blkcg_policy_data *cpd; 1246 1247 /* 1248 * If the policy hasn't been attached yet, wait for it 1249 * to be attached before doing anything else. Otherwise, 1250 * check if the policy requires any specific per-cgroup 1251 * data: if it does, allocate and initialize it. 1252 */ 1253 if (!pol || !pol->cpd_alloc_fn) 1254 continue; 1255 1256 cpd = pol->cpd_alloc_fn(GFP_KERNEL); 1257 if (!cpd) { 1258 ret = ERR_PTR(-ENOMEM); 1259 goto free_pd_blkcg; 1260 } 1261 blkcg->cpd[i] = cpd; 1262 cpd->blkcg = blkcg; 1263 cpd->plid = i; 1264 if (pol->cpd_init_fn) 1265 pol->cpd_init_fn(cpd); 1266 } 1267 1268 spin_lock_init(&blkcg->lock); 1269 refcount_set(&blkcg->online_pin, 1); 1270 INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN); 1271 INIT_HLIST_HEAD(&blkcg->blkg_list); 1272 #ifdef CONFIG_CGROUP_WRITEBACK 1273 INIT_LIST_HEAD(&blkcg->cgwb_list); 1274 #endif 1275 list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs); 1276 1277 mutex_unlock(&blkcg_pol_mutex); 1278 return &blkcg->css; 1279 1280 free_pd_blkcg: 1281 for (i--; i >= 0; i--) 1282 if (blkcg->cpd[i]) 1283 blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]); 1284 free_percpu(blkcg->lhead); 1285 free_blkcg: 1286 if (blkcg != &blkcg_root) 1287 kfree(blkcg); 1288 unlock: 1289 mutex_unlock(&blkcg_pol_mutex); 1290 return ret; 1291 } 1292 -- 0-DAY CI Kernel Test Service https://01.org/lkp