Merge tag 'mm-hotfixes-stable-2023-08-25-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "18 hotfixes. 13 are cc:stable and the remainder pertain to post-6.4
  issues or aren't considered suitable for a -stable backport"

* tag 'mm-hotfixes-stable-2023-08-25-11-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  shmem: fix smaps BUG sleeping while atomic
  selftests: cachestat: catch failing fsync test on tmpfs
  selftests: cachestat: test for cachestat availability
  maple_tree: disable mas_wr_append() when other readers are possible
  madvise:madvise_free_pte_range(): don't use mapcount() against large folio for sharing check
  madvise:madvise_free_huge_pmd(): don't use mapcount() against large folio for sharing check
  madvise:madvise_cold_or_pageout_pte_range(): don't use mapcount() against large folio for sharing check
  mm: multi-gen LRU: don't spin during memcg release
  mm: memory-failure: fix unexpected return value in soft_offline_page()
  radix tree: remove unused variable
  mm: add a call to flush_cache_vmap() in vmap_pfn()
  selftests/mm: FOLL_LONGTERM need to be updated to 0x100
  nilfs2: fix general protection fault in nilfs_lookup_dirty_data_buffers()
  mm/gup: handle cont-PTE hugetlb pages correctly in gup_must_unshare() via GUP-fast
  selftests: cgroup: fix test_kmem_basic less than error
  mm: enable page walking API to lock vmas during the walk
  smaps: use vm_normal_page_pmd() instead of follow_trans_huge_pmd()
  mm/gup: reintroduce FOLL_NUMA as FOLL_HONOR_NUMA_FAULT

1 files changed, 9 insertions, 5 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1080209a568b..2fe4a11d63f4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4284,6 +4284,7 @@ static void walk_mm(struct lruvec *lruvec, struct mm_struct *mm, struct lru_gen_
 	static const struct mm_walk_ops mm_walk_ops = {
 		.test_walk = should_skip_vma,
 		.p4d_entry = walk_pud_range,
+		.walk_lock = PGWALK_RDLOCK,
 	};
 
 	int err;
@@ -4853,16 +4854,17 @@ void lru_gen_release_memcg(struct mem_cgroup *memcg)
 
 		spin_lock_irq(&pgdat->memcg_lru.lock);
 
-		VM_WARN_ON_ONCE(hlist_nulls_unhashed(&lruvec->lrugen.list));
+		if (hlist_nulls_unhashed(&lruvec->lrugen.list))
+			goto unlock;
 
 		gen = lruvec->lrugen.gen;
 
-		hlist_nulls_del_rcu(&lruvec->lrugen.list);
+		hlist_nulls_del_init_rcu(&lruvec->lrugen.list);
 		pgdat->memcg_lru.nr_memcgs[gen]--;
 
 		if (!pgdat->memcg_lru.nr_memcgs[gen] && gen == get_memcg_gen(pgdat->memcg_lru.seq))
 			WRITE_ONCE(pgdat->memcg_lru.seq, pgdat->memcg_lru.seq + 1);
-
+unlock:
 		spin_unlock_irq(&pgdat->memcg_lru.lock);
 	}
 }
@@ -5434,8 +5436,10 @@ restart:
 	rcu_read_lock();
 
 	hlist_nulls_for_each_entry_rcu(lrugen, pos, &pgdat->memcg_lru.fifo[gen][bin], list) {
-		if (op)
+		if (op) {
 			lru_gen_rotate_memcg(lruvec, op);
+			op = 0;
+		}
 
 		mem_cgroup_put(memcg);
 
@@ -5443,7 +5447,7 @@ restart:
 		memcg = lruvec_memcg(lruvec);
 
 		if (!mem_cgroup_tryget(memcg)) {
-			op = 0;
+			lru_gen_release_memcg(memcg);
 			memcg = NULL;
 			continue;
 		}