In the Linux kernel, the following vulnerability has been resolved:
userfaultfd: change srcfolio after ensuring it's unpinned in UFFDIOMOVE
Commit d7a08838ab74 ("mm: userfaultfd: fix unexpected change to srcfolio when UFFDIOMOVE fails") moved the src_folio->{mapping, index} changing to after clearing the page-table and ensuring that it's not pinned. This avoids failure of swapout+migration and possibly memory corruption.
However, the commit missed fixing it in the huge-page case.