CVE-2025-39754

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

mm/smaps: fix race between smaps_hugetlb_range and migration

smaps_hugetlb_range() handles the pte without holdling ptl, and may be
concurrenct with migration, leaing to BUG_ON in pfn_swap_entry_to_page().
The race is as follows.

smaps_hugetlb_range migrate_pages
huge_ptep_get
remove_migration_ptes
folio_unlock
pfn_swap_entry_folio
BUG_ON

To fix it, hold ptl lock in smaps_hugetlb_range().