CVE-2025-21931

/// Technical description

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

hwpoison, memory_hotplug: lock folio before unmap hwpoisoned folio

Commit b15c87263a69 ("hwpoison, memory_hotplug: allow hwpoisoned pages to

be offlined) add page poison checks in do_migrate_range in order to make

offline hwpoisoned page possible by introducing isolate_lru_page and

try_to_unmap for hwpoisoned page. However folio lock must be held before

calling try_to_unmap. Add it to fix this problem.

Warning will be produced if folio is not locked during unmap:

------------[ cut here ]------------

kernel BUG at ./include/linux/swapops.h:400!

Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP

Modules linked in:

CPU: 4 UID: 0 PID: 411 Comm: bash Tainted: G W 6.13.0-rc1-00016-g3c434c7ee82a-dirty #41

Tainted: [W]=WARN

Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015

pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)

pc : try_to_unmap_one+0xb08

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References