CVE-2024-36000

In the Linux kernel, the following vulnerability has been resolved:
mm/hugetlb: fix missing hugetlb_lock for resv uncharge There is a recent
report on UFFDIO_COPY over hugetlb:
https://lore.kernel.org/all/[email protected]/ 350:
lockdep_assert_held(&hugetlb_lock); Should be an issue in hugetlb but
triggered in an userfault context, where it goes into the unlikely path
where two threads modifying the resv map together. Mike has a fix in that
path for resv uncharge but it looks like the locking criteria was
overlooked: hugetlb_cgroup_uncharge_folio_rsvd() will update the cgroup
pointer, so it requires to be called with the lock held.