netdev - [PATCH v2 08/37] mm/hugetlb: check for unreasonable folio sizes when registering hstate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250901150359.867252-9-david@redhat.com>
Date: Mon,  1 Sep 2025 17:03:29 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: David Hildenbrand <david@...hat.com>,
	Zi Yan <ziy@...dia.com>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Alexander Potapenko <glider@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Brendan Jackman <jackmanb@...gle.com>,
	Christoph Lameter <cl@...two.org>,
	Dennis Zhou <dennis@...nel.org>,
	Dmitry Vyukov <dvyukov@...gle.com>,
	dri-devel@...ts.freedesktop.org,
	intel-gfx@...ts.freedesktop.org,
	iommu@...ts.linux.dev,
	io-uring@...r.kernel.org,
	Jason Gunthorpe <jgg@...dia.com>,
	Jens Axboe <axboe@...nel.dk>,
	Johannes Weiner <hannes@...xchg.org>,
	John Hubbard <jhubbard@...dia.com>,
	kasan-dev@...glegroups.com,
	kvm@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-arm-kernel@...s.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-crypto@...r.kernel.org,
	linux-ide@...r.kernel.org,
	linux-kselftest@...r.kernel.org,
	linux-mips@...r.kernel.org,
	linux-mmc@...r.kernel.org,
	linux-mm@...ck.org,
	linux-riscv@...ts.infradead.org,
	linux-s390@...r.kernel.org,
	linux-scsi@...r.kernel.org,
	Marco Elver <elver@...gle.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Michal Hocko <mhocko@...e.com>,
	Mike Rapoport <rppt@...nel.org>,
	Muchun Song <muchun.song@...ux.dev>,
	netdev@...r.kernel.org,
	Oscar Salvador <osalvador@...e.de>,
	Peter Xu <peterx@...hat.com>,
	Robin Murphy <robin.murphy@....com>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Tejun Heo <tj@...nel.org>,
	virtualization@...ts.linux.dev,
	Vlastimil Babka <vbabka@...e.cz>,
	wireguard@...ts.zx2c4.com,
	x86@...nel.org
Subject: [PATCH v2 08/37] mm/hugetlb: check for unreasonable folio sizes when registering hstate

Let's check that no hstate that corresponds to an unreasonable folio size
is registered by an architecture. If we were to succeed registering, we
could later try allocating an unsupported gigantic folio size.

Further, let's add a BUILD_BUG_ON() for checking that HUGETLB_PAGE_ORDER
is sane at build time. As HUGETLB_PAGE_ORDER is dynamic on powerpc, we have
to use a BUILD_BUG_ON_INVALID() to make it compile.

No existing kernel configuration should be able to trigger this check:
either SPARSEMEM without SPARSEMEM_VMEMMAP cannot be configured or
gigantic folios will not exceed a memory section (the case on sparse).

Reviewed-by: Zi Yan <ziy@...dia.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 mm/hugetlb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1e777cc51ad04..d3542e92a712e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4657,6 +4657,7 @@ static int __init hugetlb_init(void)
 
 	BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE <
 			__NR_HPAGEFLAGS);
+	BUILD_BUG_ON_INVALID(HUGETLB_PAGE_ORDER > MAX_FOLIO_ORDER);
 
 	if (!hugepages_supported()) {
 		if (hugetlb_max_hstate || default_hstate_max_huge_pages)
@@ -4740,6 +4741,7 @@ void __init hugetlb_add_hstate(unsigned int order)
 	}
 	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
 	BUG_ON(order < order_base_2(__NR_USED_SUBPAGE));
+	WARN_ON(order > MAX_FOLIO_ORDER);
 	h = &hstates[hugetlb_max_hstate++];
 	__mutex_init(&h->resize_lock, "resize mutex", &h->resize_key);
 	h->order = order;
-- 
2.50.1