kernel: Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass RO checks

A flaw was found in the Linux kernel’s KVM implementation, where improper handing of the VMIO|VMPFNMAP VMAs in KVM bypasses RO checks and leads to pages being freed while still accessible by the VMM and guest. This flaw allows users who can start and control a VM to read/write random pages of...