Kernel: KVM: nVMX: use-after-free of the hrtimer for emulation of the preemption timer

A use-after-free vulnerability was found in the way the Linux kernel's KVM hypervisor emulates a preemption timer for L2 guests when nested =1 virtualization is enabled. This high resolution timerhrtimer runs when a L2 guest is active. After VM exit, the syncvmcs12 timer object is stopped. The...