CVE-2026-93230: mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier

CVE-2026-93230: mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier

Gigantic bootmem HugeTLB pages are currently initialized from
hugetlb_init(), but page_alloc_init_late() runs earlier and walks
pageblocks to determine zone contiguity.

If a bootmem HugeTLB region is marked noinit, set_zone_contiguous() can
observe still-uninitialized struct pages through
__pageblock_pfn_to_page().  This may not trigger an immediate failure, but
it can make set_zone_contiguous() compute the wrong zone contiguity state.
If extra poisoned-page checks are added in this path, such as
PF_POISONED_CHECK() in page_zone_id(), it can also trigger an early boot
panic.

Initialize gigantic bootmem HugeTLB struct pages from
page_alloc_init_late(), before zone contiguity is evaluated, so later page
allocator setup only sees valid struct page state.  This also makes the
initialization order more natural, as struct pages should be initialized
before later code inspects them.

The Linux kernel CVE team has assigned CVE-2026-93230 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.7 with commit fde1c4ecf91640e5a95ec36b71ec2e8ec379ce40 and fixed in 6.18.51 with commit 09505232eced5f1c42902d8f28740f070c3fc6dc
	Issue introduced in 6.7 with commit fde1c4ecf91640e5a95ec36b71ec2e8ec379ce40 and fixed in 7.2.4 with commit 29968bc7aefb3cf1e72aa7c5f52697a6b0527094
	Issue introduced in 6.7 with commit fde1c4ecf91640e5a95ec36b71ec2e8ec379ce40 and fixed in 7.3-rc1 with commit b1b7c045e808c761b1cc8c19b3040fadedda3fef

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-93230
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	include/linux/hugetlb.h
	mm/hugetlb.c
	mm/mm_init.c
	mm/sparse-vmemmap.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/09505232eced5f1c42902d8f28740f070c3fc6dc
	https://git.kernel.org/stable/c/29968bc7aefb3cf1e72aa7c5f52697a6b0527094
	https://git.kernel.org/stable/c/b1b7c045e808c761b1cc8c19b3040fadedda3fef