CVE-2025-40353

About vulnerability

In the Linux kernel, the following vulnerability has been resolved: arm64: mte: Do not warn if the page is already tagged in copy_highpage() The arm64 copy_highpage() assumes that the destination page is newly allocated and not MTE-tagged (PG_mte_tagged unset) and warns accordingly. However, following commit 060913999d7a (“mm: migrate: support poisoned recover from migrate folio”), folio_mc_copy() is called before __folio_migrate_mapping(). If the latter fails (-EAGAIN), the copy will be done again to the same destination page. Since copy_highpage() already set the PG_mte_tagged flag, this second copy will warn. Replace the WARN_ON_ONCE(page already tagged) in the arm64 copy_highpage() with a comment. A flaw was found in the Linux kernel’s arm64 copy_highpage() implementation related to Memory Tagging Extensionflag handling. The function previously assumed that a destination page for a copy operation would always be newly allocated and untagged. Under certain memory migration paths, this assumption no longer holds, and copy_highpage() could generate extraneous WARN_ON_ONCE() messages if the page was already MTE-tagged.

Live-patch status from KernelCare for each operating system.