diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 7971225eb8ffbce6b393aa3d3945f576d5acb5f7..4511d26fc28dfa610473a9cf58f677cbf734fa08 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3620,18 +3620,38 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
 	return ret;
 }
 
-void __folio_undo_large_rmappable(struct folio *folio)
+/*
+ * __folio_unqueue_deferred_split() is not to be called directly:
+ * the folio_unqueue_deferred_split() inline wrapper in mm/internal.h
+ * limits its calls to those folios which may have a _deferred_list for
+ * queueing THP splits, and that list is (racily observed to be) non-empty.
+ *
+ * It is unsafe to call folio_unqueue_deferred_split() until folio refcount is
+ * zero: because even when split_queue_lock is held, a non-empty _deferred_list
+ * might be in use on deferred_split_scan()'s unlocked on-stack list.
+ *
+ * If memory cgroups are enabled, split_queue_lock is in the mem_cgroup: it is
+ * therefore important to unqueue deferred split before changing folio memcg.
+ */
+bool __folio_unqueue_deferred_split(struct folio *folio)
 {
 	struct deferred_split *ds_queue;
 	unsigned long flags;
+	bool unqueued = false;
+
+	WARN_ON_ONCE(folio_ref_count(folio));
+	WARN_ON_ONCE(!mem_cgroup_disabled() && !folio_memcg(folio));
 
 	ds_queue = get_deferred_split_queue(folio);
 	spin_lock_irqsave(&ds_queue->split_queue_lock, flags);
 	if (!list_empty(&folio->_deferred_list)) {
 		ds_queue->split_queue_len--;
 		list_del_init(&folio->_deferred_list);
+		unqueued = true;
 	}
 	spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags);
+
+	return unqueued;	/* useful for debug warnings */
 }
 
 void deferred_split_folio(struct folio *folio)
@@ -3650,14 +3670,11 @@ void deferred_split_folio(struct folio *folio)
 		return;
 
 	/*
-	 * The try_to_unmap() in page reclaim path might reach here too,
-	 * this may cause a race condition to corrupt deferred split queue.
-	 * And, if page reclaim is already handling the same folio, it is
-	 * unnecessary to handle it again in shrinker.
-	 *
-	 * Check the swapcache flag to determine if the folio is being
-	 * handled by page reclaim since THP swap would add the folio into
-	 * swap cache before calling try_to_unmap().
+	 * Exclude swapcache: originally to avoid a corrupt deferred split
+	 * queue. Nowadays that is fully prevented by mem_cgroup_swapout();
+	 * but if page reclaim is already handling the same folio, it is
+	 * unnecessary to handle it again in the shrinker, so excluding
+	 * swapcache here may still be a useful optimization.
 	 */
 	if (folio_test_swapcache(folio))
 		return;
diff --git a/mm/internal.h b/mm/internal.h
index 2803e754c3e873450ebab56181f3eb9cd5568a80..46c5a8da9d728af9e02ee7287b8db7dd2f4eb671 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -636,11 +636,11 @@ static inline void folio_set_order(struct folio *folio, unsigned int order)
 #endif
 }
 
-void __folio_undo_large_rmappable(struct folio *folio);
-static inline void folio_undo_large_rmappable(struct folio *folio)
+bool __folio_unqueue_deferred_split(struct folio *folio);
+static inline bool folio_unqueue_deferred_split(struct folio *folio)
 {
 	if (folio_order(folio) <= 1 || !folio_test_large_rmappable(folio))
-		return;
+		return false;
 
 	/*
 	 * At this point, there is no one trying to add the folio to
@@ -648,9 +648,9 @@ static inline void folio_undo_large_rmappable(struct folio *folio)
 	 * to check without acquiring the split_queue_lock.
 	 */
 	if (data_race(list_empty(&folio->_deferred_list)))
-		return;
+		return false;
 
-	__folio_undo_large_rmappable(folio);
+	return __folio_unqueue_deferred_split(folio);
 }
 
 static inline struct folio *page_rmappable_folio(struct page *page)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9f86404b37142ee4bba65945df81f4e4831dde0e..023d85aabfe80e74875d1c83182e7249fce5371e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -7115,6 +7115,8 @@ static int mem_cgroup_move_account(struct page *page,
 	css_get(&to->css);
 	css_put(&from->css);
 
+	/* Warning should never happen, so don't worry about refcount non-0 */
+	WARN_ON_ONCE(folio_unqueue_deferred_split(folio));
 	folio->memcg_data = (unsigned long)to;
 
 	__folio_memcg_unlock(from);
@@ -7483,7 +7485,10 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
 	enum mc_target_type target_type;
 	union mc_target target;
 	struct page *page;
+	struct folio *folio;
+	bool tried_split_before = false;
 
+retry_pmd:
 	ptl = pmd_trans_huge_lock(pmd, vma);
 	if (ptl) {
 		if (mc.precharge < HPAGE_PMD_NR) {
@@ -7493,6 +7498,28 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
 		target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
 		if (target_type == MC_TARGET_PAGE) {
 			page = target.page;
+			folio = page_folio(page);
+			/*
+			 * Deferred split queue locking depends on memcg,
+			 * and unqueue is unsafe unless folio refcount is 0:
+			 * split or skip if on the queue? first try to split.
+			 */
+			if (!list_empty(&folio->_deferred_list)) {
+				spin_unlock(ptl);
+				if (!tried_split_before)
+					split_folio(folio);
+				folio_unlock(folio);
+				folio_put(folio);
+				if (tried_split_before)
+					return 0;
+				tried_split_before = true;
+				goto retry_pmd;
+			}
+			/*
+			 * So long as that pmd lock is held, the folio cannot
+			 * be racily added to the _deferred_list, because
+			 * page_remove_rmap() will find it still pmdmapped.
+			 */
 			if (isolate_lru_page(page)) {
 				if (!mem_cgroup_move_account(page, true,
 							     mc.from, mc.to)) {
@@ -8546,9 +8573,6 @@ static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug)
 	struct obj_cgroup *objcg;
 
 	VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
-	VM_BUG_ON_FOLIO(folio_order(folio) > 1 &&
-			!folio_test_hugetlb(folio) &&
-			!list_empty(&folio->_deferred_list), folio);
 
 	/*
 	 * Nobody should be changing or seriously looking at
@@ -8595,6 +8619,7 @@ static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug)
 			ug->nr_memory += nr_pages;
 		ug->pgpgout++;
 
+		WARN_ON_ONCE(folio_unqueue_deferred_split(folio));
 		folio->memcg_data = 0;
 	}
 
@@ -8710,6 +8735,9 @@ void mem_cgroup_migrate(struct folio *old, struct folio *new)
 
 	/* Transfer the charge and the css ref */
 	commit_charge(new, memcg);
+
+	/* Warning should never happen, so don't worry about refcount non-0 */
+	WARN_ON_ONCE(folio_unqueue_deferred_split(old));
 	old->memcg_data = 0;
 }
 
@@ -8970,6 +8998,7 @@ void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry)
 	VM_BUG_ON_FOLIO(oldid, folio);
 	mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
 
+	folio_unqueue_deferred_split(folio);
 	folio->memcg_data = 0;
 
 	if (!mem_cgroup_is_root(memcg))
diff --git a/mm/migrate.c b/mm/migrate.c
index 557c496c3f922529feae701357b93755c4802b38..ace03cce4e3740dda2023b12de0979d9a4ef6138 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -413,7 +413,7 @@ static int __folio_migrate_mapping(struct address_space *mapping,
 		    folio_test_large_rmappable(folio)) {
 			if (!folio_ref_freeze(folio, expected_count))
 				return -EAGAIN;
-			folio_undo_large_rmappable(folio);
+			folio_unqueue_deferred_split(folio);
 			folio_ref_unfreeze(folio, expected_count);
 		}
 
@@ -438,7 +438,7 @@ static int __folio_migrate_mapping(struct address_space *mapping,
 	}
 
 	/* Take off deferred split queue while frozen and memcg set */
-	folio_undo_large_rmappable(folio);
+	folio_unqueue_deferred_split(folio);
 
 	/*
 	 * Now we know that no one else is looking at the folio:
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c701f1f4675e2ac2e247f44256e86ae132f9eb0a..3da0f0bc1f798498c8393efc57354c2cc7bcdc8a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2591,7 +2591,6 @@ void free_unref_folios(struct folio_batch *folios)
 			continue;
 		}
 
-		folio_undo_large_rmappable(folio);
 		if (!free_unref_page_prepare(&folio->page, pfn, order))
 			continue;
 
diff --git a/mm/swap.c b/mm/swap.c
index 3e5f88baf61ee867ce923d75f413ca8946ed9ab8..3c0e1464095154a874669aa2afe5c4db47536141 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -109,7 +109,7 @@ void __folio_put(struct folio *folio)
 	}
 
 	page_cache_release(folio);
-	folio_undo_large_rmappable(folio);
+	folio_unqueue_deferred_split(folio);
 	mem_cgroup_uncharge(folio);
 	free_unref_page(&folio->page, folio_order(folio));
 }
@@ -1003,7 +1003,7 @@ void folios_put_refs(struct folio_batch *folios, unsigned int *refs)
 			free_huge_folio(folio);
 			continue;
 		}
-		folio_undo_large_rmappable(folio);
+		folio_unqueue_deferred_split(folio);
 		__page_cache_release(folio, &lruvec, &flags);
 
 		if (j != i)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8e605361b714cf9f21ecee1ccbcef4d663abad0d..a249eeedb81256a8cfee82fdd4728473ab5fe932 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2151,7 +2151,7 @@ static unsigned int shrink_folio_list(struct list_head *folio_list,
 		 */
 		nr_reclaimed += nr_pages;
 
-		folio_undo_large_rmappable(folio);
+		folio_unqueue_deferred_split(folio);
 		if (folio_batch_add(&free_folios, folio) == 0) {
 			mem_cgroup_uncharge_folios(&free_folios);
 			try_to_unmap_flush();
@@ -2539,7 +2539,7 @@ static unsigned int move_folios_to_lru(struct lruvec *lruvec,
 		if (unlikely(folio_put_testzero(folio))) {
 			__folio_clear_lru_flags(folio);
 
-			folio_undo_large_rmappable(folio);
+			folio_unqueue_deferred_split(folio);
 			if (folio_batch_add(&free_folios, folio) == 0) {
 				spin_unlock_irq(&lruvec->lru_lock);
 				mem_cgroup_uncharge_folios(&free_folios);