From 2394aef616cf38fbf2e797c6845ccd35d76ce256 Mon Sep 17 00:00:00 2001 From: Zi Yan Date: Thu, 7 Mar 2024 13:18:54 -0500 Subject: [PATCH] mm/huge_memory: skip invalid debugfs new_order input for folio split User can put arbitrary new_order via debugfs for folio split test. Although new_order check is added to split_huge_page_to_list_order() in the prior commit, these two additional checks can avoid unnecessary folio locking and split_folio_to_order() calls. Link: https://lkml.kernel.org/r/20240307181854.138928-2-zi.yan@sent.com 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 | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 57fca7bffd20..9859aa4f7553 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3486,6 +3486,9 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start, if (!is_transparent_hugepage(folio)) goto next; + if (new_order >= folio_order(folio)) + goto next; + total++; /* * For folios with private, split_huge_page_to_list_to_order() @@ -3553,6 +3556,9 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start, total++; nr_pages = folio_nr_pages(folio); + if (new_order >= folio_order(folio)) + goto next; + if (!folio_trylock(folio)) goto next;