Hi Jesper, kernel test robot noticed the following build warnings: [auto build test WARNING on tj-cgroup/for-next] [also build test WARNING on axboe-block/for-next akpm-mm/mm-everything linus/master v6.11-rc7 next-20240909] [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/Jesper-Dangaard-Brouer/cgroup-rstat-Avoid-flushing-if-there-is-an-ongoing-root-flush/20240905-034221 base: https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next patch link: https://lore.kernel.org/r/172547884995.206112.808619042206173396.stgit%40firesoul patch subject: [PATCH V10] cgroup/rstat: Avoid flushing if there is an ongoing root flush config: hexagon-randconfig-r121-20240910 (https://download.01.org/0day-ci/archive/20240910/202409101356.VXPFCu6l-lkp@xxxxxxxxx/config) compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1) reproduce: (https://download.01.org/0day-ci/archive/20240910/202409101356.VXPFCu6l-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/202409101356.VXPFCu6l-lkp@xxxxxxxxx/ sparse warnings: (new ones prefixed by >>) >> kernel/cgroup/rstat.c:339:23: sparse: sparse: Using plain integer as NULL pointer kernel/cgroup/rstat.c:87:18: sparse: sparse: context imbalance in 'cgroup_rstat_updated' - different lock contexts for basic block kernel/cgroup/rstat.c:75:9: sparse: sparse: context imbalance in 'cgroup_rstat_updated_list' - wrong count at exit kernel/cgroup/rstat.c:320:13: sparse: sparse: context imbalance in 'cgroup_rstat_trylock_flusher' - wrong count at exit kernel/cgroup/rstat.c:300:34: sparse: sparse: context imbalance in 'cgroup_rstat_unlock_flusher' - unexpected unlock kernel/cgroup/rstat.c:373:9: sparse: sparse: context imbalance in 'cgroup_rstat_flush_locked' - different lock contexts for basic block kernel/cgroup/rstat.c:447:9: sparse: sparse: context imbalance in 'cgroup_rstat_flush_hold' - wrong count at exit kernel/cgroup/rstat.c:457:6: sparse: sparse: context imbalance in 'cgroup_rstat_flush_release' - wrong count at exit vim +339 kernel/cgroup/rstat.c 308 309 /** 310 * cgroup_rstat_trylock_flusher - Trylock that checks for on ongoing flusher 311 * @cgrp: target cgroup 312 * 313 * Function return value follow trylock semantics. Returning true when lock is 314 * obtained. Returning false when not locked and it detected flushing can be 315 * skipped as another ongoing flusher is taking care of the flush. 316 * 317 * For callers that depend on flush completing before returning a strict option 318 * is provided. 319 */ 320 static bool cgroup_rstat_trylock_flusher(struct cgroup *cgrp, bool strict) 321 { 322 struct cgroup *ongoing; 323 324 if (strict) 325 goto lock; 326 327 /* 328 * Check if ongoing flusher is already taking care of this. Descendant 329 * check is necessary due to cgroup v1 supporting multiple root's. 330 */ 331 ongoing = READ_ONCE(cgrp_rstat_ongoing_flusher); 332 if (ongoing && cgroup_is_descendant(cgrp, ongoing)) 333 return false; 334 335 /* Grab right to be ongoing flusher */ 336 if (!ongoing && cgroup_is_root(cgrp)) { 337 struct cgroup *old; 338 > 339 old = cmpxchg(&cgrp_rstat_ongoing_flusher, NULL, cgrp); 340 if (old) { 341 /* Lost race for being ongoing flusher */ 342 if (cgroup_is_descendant(cgrp, old)) 343 return false; 344 } 345 /* Due to lock yield combined with strict mode record ID */ 346 WRITE_ONCE(cgrp_rstat_ongoing_flusher_ID, current); 347 } 348 lock: 349 __cgroup_rstat_lock(cgrp, -1); 350 351 return true; 352 } 353 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
