From 1412ecb3d256e5d23c6bd150e110cef6e3736844 Mon Sep 17 00:00:00 2001 From: Zi Yan Date: Thu, 7 Mar 2024 13:18:53 -0500 Subject: mm/huge_memory: check new folio order when split a folio A folio can only be split into lower orders. Since there are no new_order checks in debugfs, any new_order can be passed via debugfs into split_huge_page_to_list_to_order(). Check new_order to make sure it is smaller than input folio order. Link: https://lkml.kernel.org/r/20240307181854.138928-1-zi.yan@sent.com Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") Signed-off-by: Zi Yan Reported-by: Dan Carpenter Closes: https://lore.kernel.org/linux-mm/7dda9283-b437-4cf8-ab0d-83c330deb9c0@moroto.mountain/ Cc: David Hildenbrand Cc: Kirill A. Shutemov Cc: Matthew Wilcox (Oracle) Cc: Ryan Roberts Cc: Yang Shi Cc: Yu Zhao Signed-off-by: Andrew Morton --- mm/huge_memory.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'mm') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a81a09236c161..57fca7bffd208 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3052,6 +3052,9 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); + if (new_order >= folio_order(folio)) + return -EINVAL; + /* Cannot split anonymous THP to order-1 */ if (new_order == 1 && folio_test_anon(folio)) { VM_WARN_ONCE(1, "Cannot split to order-1 folio"); -- cgit 1.2.3-korg