Hi Kairui, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: d082ecbc71e9e0bf49883ee4afd435a77a5101b6 commit: fb56fdf8b9a2f7397f8a83dce50189f3f0cf71af mm/list_lru: split the lock to per-cgroup scope date: 4 months ago config: mips-randconfig-r052-20250224 (https://download.01.org/0day-ci/archive/20250225/202502250720.9ueIb7Xh-lkp@xxxxxxxxx/config) compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99) 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/202502250720.9ueIb7Xh-lkp@xxxxxxxxx/ cocci warnings: (new ones prefixed by >>) >> mm/list_lru.c:552:3-8: WARNING: NULL check before some freeing functions is not needed. vim +552 mm/list_lru.c 88f2ef73fd6649 Muchun Song 2022-03-22 508 88f2ef73fd6649 Muchun Song 2022-03-22 509 int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, 88f2ef73fd6649 Muchun Song 2022-03-22 510 gfp_t gfp) 88f2ef73fd6649 Muchun Song 2022-03-22 511 { 88f2ef73fd6649 Muchun Song 2022-03-22 512 unsigned long flags; d70110704d2d52 Muchun Song 2022-03-22 513 struct list_lru_memcg *mlru; 28e98022b31efd Kairui Song 2024-11-05 514 struct mem_cgroup *pos, *parent; bbca91cca9a902 Muchun Song 2022-03-22 515 XA_STATE(xas, &lru->xa, 0); 88f2ef73fd6649 Muchun Song 2022-03-22 516 88f2ef73fd6649 Muchun Song 2022-03-22 517 if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocated(memcg, lru)) 88f2ef73fd6649 Muchun Song 2022-03-22 518 return 0; 88f2ef73fd6649 Muchun Song 2022-03-22 519 88f2ef73fd6649 Muchun Song 2022-03-22 520 gfp &= GFP_RECLAIM_MASK; 88f2ef73fd6649 Muchun Song 2022-03-22 521 /* 88f2ef73fd6649 Muchun Song 2022-03-22 522 * Because the list_lru can be reparented to the parent cgroup's 88f2ef73fd6649 Muchun Song 2022-03-22 523 * list_lru, we should make sure that this cgroup and all its d70110704d2d52 Muchun Song 2022-03-22 524 * ancestors have allocated list_lru_memcg. 88f2ef73fd6649 Muchun Song 2022-03-22 525 */ 28e98022b31efd Kairui Song 2024-11-05 526 do { 28e98022b31efd Kairui Song 2024-11-05 527 /* 28e98022b31efd Kairui Song 2024-11-05 528 * Keep finding the farest parent that wasn't populated 28e98022b31efd Kairui Song 2024-11-05 529 * until found memcg itself. 28e98022b31efd Kairui Song 2024-11-05 530 */ 28e98022b31efd Kairui Song 2024-11-05 531 pos = memcg; 28e98022b31efd Kairui Song 2024-11-05 532 parent = parent_mem_cgroup(pos); 28e98022b31efd Kairui Song 2024-11-05 533 while (!memcg_list_lru_allocated(parent, lru)) { 28e98022b31efd Kairui Song 2024-11-05 534 pos = parent; 28e98022b31efd Kairui Song 2024-11-05 535 parent = parent_mem_cgroup(pos); 88f2ef73fd6649 Muchun Song 2022-03-22 536 } 88f2ef73fd6649 Muchun Song 2022-03-22 537 fb56fdf8b9a2f7 Kairui Song 2024-11-05 538 mlru = memcg_init_list_lru_one(lru, gfp); 28e98022b31efd Kairui Song 2024-11-05 539 if (!mlru) 28e98022b31efd Kairui Song 2024-11-05 540 return -ENOMEM; 28e98022b31efd Kairui Song 2024-11-05 541 xas_set(&xas, pos->kmemcg_id); 28e98022b31efd Kairui Song 2024-11-05 542 do { bbca91cca9a902 Muchun Song 2022-03-22 543 xas_lock_irqsave(&xas, flags); 28e98022b31efd Kairui Song 2024-11-05 544 if (!xas_load(&xas) && !css_is_dying(&pos->css)) { bbca91cca9a902 Muchun Song 2022-03-22 545 xas_store(&xas, mlru); 28e98022b31efd Kairui Song 2024-11-05 546 if (!xas_error(&xas)) 28e98022b31efd Kairui Song 2024-11-05 547 mlru = NULL; bbca91cca9a902 Muchun Song 2022-03-22 548 } bbca91cca9a902 Muchun Song 2022-03-22 549 xas_unlock_irqrestore(&xas, flags); 28e98022b31efd Kairui Song 2024-11-05 550 } while (xas_nomem(&xas, gfp)); 28e98022b31efd Kairui Song 2024-11-05 551 if (mlru) 28e98022b31efd Kairui Song 2024-11-05 @552 kfree(mlru); 28e98022b31efd Kairui Song 2024-11-05 553 } while (pos != memcg && !css_is_dying(&pos->css)); 88f2ef73fd6649 Muchun Song 2022-03-22 554 bbca91cca9a902 Muchun Song 2022-03-22 555 return xas_error(&xas); 88f2ef73fd6649 Muchun Song 2022-03-22 556 } 60d3fd32a7a9da Vladimir Davydov 2015-02-12 557 #else bbca91cca9a902 Muchun Song 2022-03-22 558 static inline void memcg_init_list_lru(struct list_lru *lru, bool memcg_aware) 60d3fd32a7a9da Vladimir Davydov 2015-02-12 559 { 60d3fd32a7a9da Vladimir Davydov 2015-02-12 560 } 60d3fd32a7a9da Vladimir Davydov 2015-02-12 561 :::::: The code at line 552 was first introduced by commit :::::: 28e98022b31efdb8f1ba310d938cd9b97ededfe4 mm/list_lru: simplify reparenting and initial allocation :::::: TO: Kairui Song <kasong@xxxxxxxxxxx> :::::: CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
