CVE-2025-21907

/// Technical description

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

mm: memory-failure: update ttu flag inside unmap_poisoned_folio

Patch series "mm: memory_failure: unmap poisoned folio during migrate

properly", v3.

Fix two bugs during folio migration if the folio is poisoned.

This patch (of 3):

Commit 6da6b1d4a7df ("mm/hwpoison: convert TTU_IGNORE_HWPOISON to

TTU_HWPOISON") introduce TTU_HWPOISON to replace TTU_IGNORE_HWPOISON in

order to stop send SIGBUS signal when accessing an error page after a

memory error on a clean folio. However during page migration, anon folio

must be set with TTU_HWPOISON during unmap_*(). For pagecache we need

some policy just like the one in hwpoison_user_mappings to set this flag.

So move this policy from hwpoison_user_mappings to unmap_poisoned_folio to

handle this warning properly.

Warning will be produced during unamp poison folio with the following log:

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

WARNING: CPU: 1 PID: 365 at mm/rmap.c:1847 tr

/// 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