diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 8079676c8f1f..2912eba575d5 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -914,6 +914,10 @@ static int migrate_vma_split_unmapped_folio(struct migrate_vma *migrate,
 	unsigned long flags;
 	int ret = 0;
 
+	/*
+	 * take a reference, since split_huge_pmd_address() with freeze = true
+	 * drops a reference at the end.
+	 */
 	folio_get(folio);
 	split_huge_pmd_address(migrate->vma, addr, true);
 	ret = folio_split_unmapped(folio, 0);