The kvm_vm_ioctl_check_extension function in arch/powerpc/kvm/powerpc.c in the Linux kernel before 4.13.11 allows local users to cause a denial of service (NULL pointer dereference and system crash) via a KVM_CHECK_EXTENSION KVM_CAP_PPC_HTM ioctl call to /dev/kvm.
https://github.com/torvalds/linux/commit/ac64115a66c18c01745bbd3c47a36b124e5fd8c0
http://www.securityfocus.com/bid/101693
http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.11