A flaw was found in the way the KVM hypervisor on the Power8 processor stores the r1 register state in the ‘HSTATE_HOST_R1’ field on the Linux kernel stack. This flaw occurs while handling hypercalls in Transactional Memory ™ suspend mode in the kvmppc_save_tm and kvmppc_restore_tm routines, leading to host stack corruption. R1 register holds a stack frame address and its corruption leads the kernel into panic state. A guest user can use this flaw to crash the host kernel, resulting in a denial of service.