xeon is the host/hypervisor and it has the following boot args: sdeziel@xeon:~$ cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-4.4.0-108-generic root=UUID=40a302c9-82d9-4574-ac2f-efcf5c9d126f ro hugepages=3008 kaslr nmi_watchdog=0 possible_cpus=2 transparent_hugepage=never vsyscall=none The Trusty VM hangs during boot: sdeziel@xeon:~$ virsh start --console smtp # Trusty VM Domain smtp started Connected to domain smtp Escape character is ^] [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Initializing cgroup subsys cpuacct [ 0.000000] Linux version 3.13.0-137-generic (buildd@lgw01-amd64-058) (gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04.3) ) #186-Ubuntu SMP Mon Dec 4 19:09:19 UTC 2017 (Ubuntu 3.13.0-137.186-generic 3.13.11-ckt39) [ 0.000000] Command line: root=UUID=4c6c4ccd-99e2-43fa-af96-91bdeb1258aa ro console=ttyS0 [ 0.000000] KERNEL supported cpus: [ 0.000000] Intel GenuineIntel [ 0.000000] AMD AuthenticAMD [ 0.000000] Centaur CentaurHauls [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x0000000017fdffff] usable [ 0.000000] BIOS-e820: [mem 0x0000000017fe0000-0x0000000017ffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved [ 0.000000] NX (Execute Disable) protection: active [ 0.000000] SMBIOS 2.8 present. [ 0.000000] Hypervisor detected: KVM [ 0.000000] No AGP bridge found [ 0.000000] e820: last_pfn = 0x17fe0 max_arch_pfn = 0x400000000 [ 0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106 [ 0.000000] found SMP MP-table at [mem 0x000f6630-0x000f663f] mapped at [ffff8800000f6630] [ 0.000000] Scanning 1 areas for low memory corruption [ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff] [ 0.000000] init_memory_mapping: [mem 0x17800000-0x179fffff] [ 0.000000] init_memory_mapping: [mem 0x14000000-0x177fffff] [ 0.000000] init_memory_mapping: [mem 0x00100000-0x13ffffff] [ 0.000000] init_memory_mapping: [mem 0x17a00000-0x17fdffff] [ 0.000000] RAMDISK: [mem 0x17a62000-0x17fcffff] [ 0.000000] ACPI: RSDP 00000000000f6450 000014 (v00 BOCHS ) [ 0.000000] ACPI: RSDT 0000000017fe16fa 000034 (v01 BOCHS BXPCRSDT 00000001 BXPC 00000001) [ 0.000000] ACPI: FACP 0000000017fe0c14 000074 (v01 BOCHS BXPCFACP 00000001 BXPC 00000001) [ 0.000000] ACPI: DSDT 0000000017fe0040 000BD4 (v01 BOCHS BXPCDSDT 00000001 BXPC 00000001) [ 0.000000] ACPI: FACS 0000000017fe0000 000040 [ 0.000000] ACPI: SSDT 0000000017fe0c88 0009C2 (v01 BOCHS BXPCSSDT 00000001 BXPC 00000001) [ 0.000000] ACPI: APIC 0000000017fe164a 000078 (v01 BOCHS BXPCAPIC 00000001 BXPC 00000001) [ 0.000000] ACPI: HPET 0000000017fe16c2 000038 (v01 BOCHS BXPCHPET 00000001 BXPC 00000001) [ 0.000000] No NUMA configuration found [ 0.000000] Faking a node at [mem 0x0000000000000000-0x0000000017fdffff] [ 0.000000] Initmem setup node 0 [mem 0x00000000-0x17fdffff] [ 0.000000] NODE_DATA [mem 0x17fdb000-0x17fdffff] [ 0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00 [ 0.000000] kvm-clock: cpu 0, msr 0:17fd7001, boot clock [ 0.000000] Zone ranges: [ 0.000000] DMA [mem 0x00001000-0x00ffffff] [ 0.000000] DMA32 [mem 0x01000000-0xffffffff] [ 0.000000] Normal empty [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x00001000-0x0009efff] [ 0.000000] node 0: [mem 0x00100000-0x17fdffff] [ 0.000000] ACPI: PM-Timer IO Port: 0x608 [ 0.000000] ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled) [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1]) [ 0.000000] ACPI: IOAPIC (id[0x00] address[0xfec00000] gsi_base[0]) [ 0.000000] IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23 [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 5 global_irq 5 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level) [ 0.000000] Using ACPI (MADT) for SMP configuration information [ 0.000000] ACPI: HPET id: 0x8086a201 base: 0xfed00000 [ 0.000000] smpboot: Allowing 1 CPUs, 0 hotplug CPUs [ 0.000000] PM: Registered nosave memory: [mem 0x0009f000-0x0009ffff] [ 0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000effff] [ 0.000000] PM: Registered nosave memory: [mem 0x000f0000-0x000fffff] [ 0.000000] e820: [mem 0x18000000-0xfeffbfff] available for PCI devices [ 0.000000] Booting paravirtualized kernel on KVM [ 0.000000] setup_percpu: NR_CPUS:256 nr_cpumask_bits:256 nr_cpu_ids:1 nr_node_ids:1 [ 0.000000] PERCPU: Embedded 27 pages/cpu @ffff880017800000 s81536 r8192 d20864 u2097152 [ 0.000000] kvm-clock: cpu 0, msr 0:17fd7001, primary cpu clock [ 0.000000] KVM setup async PF for cpu 0 [ 0.000000] kvm-stealtime: cpu 0, msr 1780d000 [ 0.000000] Built 1 zonelists in Node order, mobility grouping on. Total pages: 96617 [ 0.000000] Policy zone: DMA32 [ 0.000000] Kernel command line: root=UUID=4c6c4ccd-99e2-43fa-af96-91bdeb1258aa ro console=ttyS0 [ 0.000000] PID hash table entries: 2048 (order: 2, 16384 bytes) [...] [ 0.954467] Freeing unused kernel memory: 1340K (ffffffff81d20000 - ffffffff81e6f000) [ 0.957493] Write protecting the kernel read-only data: 12288k [ 0.960320] Freeing unused kernel memory: 744K (ffff880001746000 - ffff880001800000) [ 0.963992] Freeing unused kernel memory: 672K (ffff880001b58000 - ffff880001c00000) Loading, please wait... [ 1.023453] systemd-udevd[94]: starting version 204 Begin: Loading essential drivers ... done. Begin: Running /scripts/init-premount ... done. Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done. Begin: Running /scripts/local-premount ... done. [ 1.286301] EXT4-fs (vda1): mounted filesystem with ordered data mode. Opts: (null) Begin: Running /scripts/local-bottom ... done. done. Begin: Running /scripts/init-bottom ... done. [ 1.616081] tsc: Refined TSC clocksource calibration: 3005.554 MHz [ 2.831648] random: init urandom read with 10 bits of entropy available [...] [ 3.818418] init: plymouth-upstart-bridge respawning too fast, stopped [ 9.860610] Adding 524284k swap on /dev/vda2. Priority:-1 extents:1 across:524284k FS [ 10.039864] EXT4-fs (vda1): re-mounted. Opts: errors=remount-ro And the host's dmesg has this: [...] audit: type=1400 audit(1515533104.246:51): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="libvirt-761cbbd4-d9f6-bc4f-8cd0-6462c4cf1e0c" pid=9934 comm="apparmor_parser" audit: type=1400 audit(1515533104.262:52): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="libvirt-761cbbd4-d9f6-bc4f-8cd0-6462c4cf1e0c//qemu_bridge_helper" pid=9934 comm="apparmo kvm: zapping shadow pages for mmio generation wraparound kvm: zapping shadow pages for mmio generation wraparound kvm [9937]: vcpu0 unhandled rdmsr: 0x345 kvm [9937]: vcpu0 unhandled wrmsr: 0x40 data 0 kvm [9937]: vcpu0 unhandled wrmsr: 0x60 data 0 kvm [9937]: vcpu0 unhandled wrmsr: 0x41 data 0 kvm [9937]: vcpu0 unhandled wrmsr: 0x61 data 0 kvm [9937]: vcpu0 unhandled wrmsr: 0x42 data 0 kvm [9937]: vcpu0 unhandled wrmsr: 0x62 data 0 kvm [9937]: vcpu0 unhandled wrmsr: 0x43 data 0 kvm [9937]: vcpu0 unhandled wrmsr: 0x63 data 0 ------------[ cut here ]------------ kernel BUG at /build/linux-J4_1pC/linux-4.4.0/mm/slub.c:3627! invalid opcode: 0000 [#1] SMP Modules linked in: nf_log_ipv6 ip6table_filter ip6_tables nf_log_ipv4 nf_log_common xt_LOG xt_tcpudp xt_owner xt_conntrack iptable_filter ip_tables x_tables zfs(PO) zunicode(PO) zcommon(PO) znvpair(PO) sp CPU: 0 PID: 9942 Comm: qemu-system-x86 Tainted: P O 4.4.0-108-generic #131-Ubuntu Hardware name: System manufacturer P5E-VM HDMI/P5E-VM HDMI, BIOS 0709 03/26/2010 task: ffff88015eb15940 ti: ffff88015ba34000 task.ti: ffff88015ba34000 RIP: 0010:[] [] kfree+0x147/0x150 RSP: 0018:ffff88015ba37bb8 EFLAGS: 00010246 RAX: ffffea0008bf0120 RBX: ffff88022fc04840 RCX: ffff88022fff5a60 RDX: ffffea00000fd020 RSI: ffffea0000097020 RDI: ffffea0008bf0100 RBP: ffff88015ba37bd0 R08: 0000000000000009 R09: ff80003fffffffff R10: ffffea0008bf0100 R11: 0000000000000001 R12: 0000000000000000 R13: ffffffffa10104ff R14: ffffffffa1f3c840 R15: 0000000000000003 FS: 00007f059efc6700(0000) GS:ffff88022fc00000(0000) knlGS:ffff880017800000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0d0f8850d0 CR3: 0000000003dec000 CR4: 0000000000002670 Stack: 0000000000000000 0000000000000000 000000000000d440 ffff88015ba37c00 ffffffffa10104ff 0000000000000002 0000000000000186 0000000000000001 ffffffff80000001 ffff88015ba37c20 ffffffffa100608f ffff88016357b800 Call Trace: [] release_ds_buffers+0xbf/0xd0 [] x86_release_hardware+0x8f/0xa0 [] hw_perf_event_destroy+0xe/0x20 [] _free_event+0xb6/0x230 [] put_event+0xc3/0x100 [] perf_event_release_kernel+0x9/0x10 [] reprogram_fixed_counter+0x6d/0x110 [kvm] [] reprogram_counter+0x4a/0x60 [kvm] [] kvm_pmu_handle_event+0x5e/0xd0 [kvm] [] vcpu_enter_guest+0xb75/0x1130 [kvm] [] kvm_arch_vcpu_ioctl_run+0xdf/0x400 [kvm] [] kvm_vcpu_ioctl+0x33d/0x620 [kvm] [] ? seccomp_phase1+0xa3/0x4a0 [] do_vfs_ioctl+0x29f/0x490 [] ? syscall_trace_enter_phase1+0xc8/0x140 [] SyS_ioctl+0x79/0x90 [] entry_SYSCALL_64_fastpath+0x16/0x8d Code: 4c 89 d7 e8 9c 83 fa ff eb 8c 41 b8 01 00 00 00 48 89 d9 48 89 da 4c 89 d6 e8 06 fc ff ff e9 73 ff ff ff 49 8b 42 20 a8 01 75 c7 <0f> 0b 0f 1f 80 00 00 00 00 66 66 66 66 90 55 48 89 e5 41 57 41 RIP [] kfree+0x147/0x150 RSP ---[ end trace a252ac79e42a18ac ]---