Commit 99132d24 authored by David Hildenbrand's avatar David Hildenbrand Committed by Andrew Morton
Browse files

mm: sanity-check maximum folio size in folio_set_order() 

Let's sanity-check in folio_set_order() whether we would be trying to
create a folio with an order that would make it exceed MAX_FOLIO_ORDER.

This will enable the check whenever a folio/compound page is initialized
through prepare_compound_head() / prepare_compound_page() with
CONFIG_DEBUG_VM set.

Link: https://lkml.kernel.org/r/20250901150359.867252-11-david@redhat.com


Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarZi Yan <ziy@nvidia.com>
Reviewed-by: default avatarWei Yang <richard.weiyang@gmail.com>
Reviewed-by: default avatarLorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: default avatarLiam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 50765b46

mm/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -755,6 +755,7 @@ static inline void folio_set_order(struct folio *folio, unsigned int order) 
{

	if (WARN_ON_ONCE(!order || !folio_test_large(folio)))

		return;

	VM_WARN_ON_ONCE(order > MAX_FOLIO_ORDER);



	folio->_flags_1 = (folio->_flags_1 & ~0xffUL) | order;

#ifdef NR_PAGES_IN_LARGE_FOLIO