---
id: CVE-2025-38029
title: 'kasan: avoid sleepable page allocation from atomic context'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  kasan: avoid sleepable page allocation from atomic context

  apply_to_pte_range() enters the lazy MMU mode and then invokes
  kasan_populate_vmalloc_pte() callback on each…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 <
    d6a895d88fbd453dc8f1c5e038188b49b272afe6
  - >-
    Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 <
    c33a7fe6dda591694cebfe15abf4644abb4f61c0
  - >-
    Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 <
    468e7d51dba433a72dcd63eee6db9ad721d39ac5
  - >-
    Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 <
    6748dd09196248b985cca39eaf651d5317271977
  - >-
    Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 <
    b6ea95a34cbd014ab6ade4248107b86b0aaf2d6c
  - Linux 5.5
published: '2025-06-18'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:21:32.818Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-38029'
references:
  - url: 'https://git.kernel.org/stable/c/d6a895d88fbd453dc8f1c5e038188b49b272afe6'
  - url: 'https://git.kernel.org/stable/c/c33a7fe6dda591694cebfe15abf4644abb4f61c0'
  - url: 'https://git.kernel.org/stable/c/468e7d51dba433a72dcd63eee6db9ad721d39ac5'
  - url: 'https://git.kernel.org/stable/c/6748dd09196248b985cca39eaf651d5317271977'
  - url: 'https://git.kernel.org/stable/c/b6ea95a34cbd014ab6ade4248107b86b0aaf2d6c'
tags:
  - cve.org
epss: 0.00237
epssPercentile: 0.14746
ingestedAt: '2026-10-21T12:48:53.708Z'
---

## Overview

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

kasan: avoid sleepable page allocation from atomic context

apply_to_pte_range() enters the lazy MMU mode and then invokes
kasan_populate_vmalloc_pte() callback on each page table walk iteration. 
However, the callback can go into sleep when trying to allocate a single
page, e.g.  if an architecutre disables preemption on lazy MMU mode enter.

On s390 if make arch_enter_lazy_mmu_mode() -> preempt_enable() and
arch_leave_lazy_mmu_mode() -> preempt_disable(), such crash occurs:

[    0.663336] BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:321
[    0.663348] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2, name: kthreadd
[    0.663358] preempt_count: 1, expected: 0
[    0.663366] RCU nest depth: 0, expected: 0
[    0.663375] no locks held by kthreadd/2.
[    0.663383] Preemption disabled at:
[    0.663386] [<0002f3284cbb4eda>] apply_to_pte_range+0xfa/0x4a0
[    0.663405] CPU: 0 UID: 0 PID: 2 Comm: kthreadd Not tainted 6.15.0-rc5-gcc-kasan-00043-gd76bb1ebb558-dirty #162 PREEMPT
[    0.663408] Hardware name: IBM 3931 A01 701 (KVM/Linux)
[    0.663409] Call Trace:
[    0.663410]  [<0002f3284c385f58>] dump_stack_lvl+0xe8/0x140
[    0.663413]  [<0002f3284c507b9e>] __might_resched+0x66e/0x700
[    0.663415]  [<0002f3284cc4f6c0>] __alloc_frozen_pages_noprof+0x370/0x4b0
[    0.663419]  [<0002f3284ccc73c0>] alloc_pages_mpol+0x1a0/0x4a0
[    0.663421]  [<0002f3284ccc8518>] alloc_frozen_pages_noprof+0x88/0xc0
[    0.663424]  [<0002f3284ccc8572>] alloc_pages_noprof+0x22/0x120
[    0.663427]  [<0002f3284cc341ac>] get_free_pages_noprof+0x2c/0xc0
[    0.663429]  [<0002f3284cceba70>] kasan_populate_vmalloc_pte+0x50/0x120
[    0.663433]  [<0002f3284cbb4ef8>] apply_to_pte_range+0x118/0x4a0
[    0.663435]  [<0002f3284cbc7c14>] apply_to_pmd_range+0x194/0x3e0
[    0.663437]  [<0002f3284cbc99be>] __apply_to_page_range+0x2fe/0x7a0
[    0.663440]  [<0002f3284cbc9e88>] apply_to_page_range+0x28/0x40
[    0.663442]  [<0002f3284ccebf12>] kasan_populate_vmalloc+0x82/0xa0
[    0.663445]  [<0002f3284cc1578c>] alloc_vmap_area+0x34c/0xc10
[    0.663448]  [<0002f3284cc1c2a6>] __get_vm_area_node+0x186/0x2a0
[    0.663451]  [<0002f3284cc1e696>] __vmalloc_node_range_noprof+0x116/0x310
[    0.663454]  [<0002f3284cc1d950>] __vmalloc_node_noprof+0xd0/0x110
[    0.663457]  [<0002f3284c454b88>] alloc_thread_stack_node+0xf8/0x330
[    0.663460]  [<0002f3284c458d56>] dup_task_struct+0x66/0x4d0
[    0.663463]  [<0002f3284c45be90>] copy_process+0x280/0x4b90
[    0.663465]  [<0002f3284c460940>] kernel_clone+0xd0/0x4b0
[    0.663467]  [<0002f3284c46115e>] kernel_thread+0xbe/0xe0
[    0.663469]  [<0002f3284c4e440e>] kthreadd+0x50e/0x7f0
[    0.663472]  [<0002f3284c38c04a>] __ret_from_fork+0x8a/0xf0
[    0.663475]  [<0002f3284ed57ff2>] ret_from_fork+0xa/0x38

Instead of allocating single pages per-PTE, bulk-allocate the shadow
memory prior to applying kasan_populate_vmalloc_pte() callback on a page
range.

## Affected

- `Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 < d6a895d88fbd453dc8f1c5e038188b49b272afe6`
- `Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 < c33a7fe6dda591694cebfe15abf4644abb4f61c0`
- `Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 < 468e7d51dba433a72dcd63eee6db9ad721d39ac5`
- `Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 < 6748dd09196248b985cca39eaf651d5317271977`
- `Linux >= 3c5c3cfb9ef4da957e3357a2bd36f76ee34c0862 < b6ea95a34cbd014ab6ade4248107b86b0aaf2d6c`
- `Linux 5.5`

## Remediation

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