CVE-2021-38200

El archivo arch/powerpc/perf/core-book3s.c en el kernel de Linux versiones anteriores a 5.12.13, en sistemas con perf_event_paranoid=-1 y sin soporte específico de controlador PMU registrado, permite a usuarios locales causar una denegación de servicio (desreferencia de puntero NULL perf_instruction_pointer y OOPS) por medio de un comando "perf record"

Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory. Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory. Various other issues were also addressed.