* Re: [PATCH v2 2/2] blk-cgroup: Optimize blkcg_rstat_flush()
[not found] <20220601165324.60892-2-longman@redhat.com>
@ 2022-06-02 1:52 ` kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2022-06-02 1:52 UTC (permalink / raw)
To: Waiman Long, Tejun Heo, Jens Axboe
Cc: llvm, kbuild-all, cgroups, linux-block, linux-kernel, Ming Lei,
Waiman Long
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 <lkp@intel.com>
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
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