From: Zi Yan <ziy@nvidia.com> mainline inclusion from mainline-v6.9-rc1 commit 2394aef616cf38fbf2e797c6845ccd35d76ce256 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9S4Z4 CVE: NA ------------------------------------------------- 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 <ziy@nvidia.com> Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/linux-mm/7dda9283-b437-4cf8-ab0d-83c330deb9c0@moroto... Cc: David Hildenbrand <david@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> (cherry picked from commit 2394aef616cf38fbf2e797c6845ccd35d76ce256) Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> --- mm/huge_memory.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b1eda738509c..fe812b3e38f7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3604,6 +3604,9 @@ 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() @@ -3671,6 +3674,9 @@ 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; -- 2.27.0