kernel: xen/privcmd: fix double free via VMA splitting

A flaw was found in the Linux kernel's xen/privcmd module. A local user could exploit this by performing a partial unmapping of a privcmd memory region. This action causes a Virtual Memory Area VMA to split, leading to duplicated internal memory pointers. As a result, the same memory can be freed...

UBUNTU-CVE-2025-38084

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb: unshare page tables during VMA split, not before Currently, splitvma triggers hugetlb page table unsharing through vmops-maysplit. This happens before the VMA lock and rmap locks are taken - which is too early, it...