---
id: CVE-2026-53154
title: 'mm/hugetlb: restore reservation on error in hugetlb folio copy paths'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  mm/hugetlb: restore reservation on error in hugetlb folio copy paths

  Two sites in mm/hugetlb.c allocate a hugetlb folio via
  alloc_hugetlb_folio() (consuming a VMA rese…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e <
    8d6e1dd3ad1340cd8b6d554b7aa93d8f0a1c6d38
  - >-
    Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e <
    e47bf16af3c45470ea32f2241fa69aefe0dd61bd
  - >-
    Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e <
    c72469ac0f274bde3f0df60a4584e14a123d0aa6
  - >-
    Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e <
    45e33d43243d71d089af42f5077b8213cee6610f
  - >-
    Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e <
    40c81856e622a9dc59294a90d169ac07ea25b0b0
  - Linux 6.4
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:21:15.298578Z'
published: '2026-06-25'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:24:05.309Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-53154'
references:
  - url: 'https://git.kernel.org/stable/c/8d6e1dd3ad1340cd8b6d554b7aa93d8f0a1c6d38'
  - url: 'https://git.kernel.org/stable/c/e47bf16af3c45470ea32f2241fa69aefe0dd61bd'
  - url: 'https://git.kernel.org/stable/c/c72469ac0f274bde3f0df60a4584e14a123d0aa6'
  - url: 'https://git.kernel.org/stable/c/45e33d43243d71d089af42f5077b8213cee6610f'
  - url: 'https://git.kernel.org/stable/c/40c81856e622a9dc59294a90d169ac07ea25b0b0'
tags:
  - cve.org
epss: 0.00122
epssPercentile: 0.01992
ingestedAt: '2026-11-06T16:57:43.275Z'
---

## Overview

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

mm/hugetlb: restore reservation on error in hugetlb folio copy paths

Two sites in mm/hugetlb.c allocate a hugetlb folio via
alloc_hugetlb_folio() (consuming a VMA reservation) and then call
copy_user_large_folio(), which became int-returning in commit 1cb9dc4b475c
("mm: hwpoison: support recovery from HugePage copy-on-write faults") and
can now fail (e.g.  -EHWPOISON on a hwpoisoned source page).  On the
failure path, folio_put() restores the global hugetlb pool count through
free_huge_folio(), but the per-VMA reservation map entry is left marked
consumed:

  - hugetlb_mfill_atomic_pte() resubmission path (UFFDIO_COPY)
  - copy_hugetlb_page_range() fork-time CoW path when
    hugetlb_try_dup_anon_rmap() fails (rare: pinned hugetlb anon
    folio under fork)

User-visible effect: on UFFDIO_COPY into a private hugetlb VMA where the
resubmission copy fails, the reservation for that address is leaked from
the VMA's reserve map.  A subsequent fault at the same address takes the
no-reservation path, and under hugetlb pool pressure the task is SIGBUSed
at an address it had previously reserved.  The fork-time CoW path leaks
the same way in the child VMA's reserve map, though it requires the much
rarer combination of pinned hugetlb anon page + hwpoisoned source.

Add the missing restore_reserve_on_error() call before folio_put() on both
error paths.

## Affected

- `Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e < 8d6e1dd3ad1340cd8b6d554b7aa93d8f0a1c6d38`
- `Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e < e47bf16af3c45470ea32f2241fa69aefe0dd61bd`
- `Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e < c72469ac0f274bde3f0df60a4584e14a123d0aa6`
- `Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e < 45e33d43243d71d089af42f5077b8213cee6610f`
- `Linux >= 1cb9dc4b475c7418f925ab0c97b6750007d9f52e < 40c81856e622a9dc59294a90d169ac07ea25b0b0`
- `Linux 6.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.