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[Bug 1578079] [NEW] Ubuntu Xenial guests segfault on hosts with CPUs supporting AVX2

 

Public bug reported:

Description
===========
When creating an Ubuntu Xenial instance from the official cloud image (https://cloud-images.ubuntu.com/xenial/current/), I noticed that sometimes it would boot just fine, sometimes it would crash almost immediately with a segmentation fault. After some investigation, I noticed that Xenial guest were crashing when running on my more recent hypervisors (Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz), while they would run just fine on my older hypervisors (Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz).

The difference between those two CPUs is that the newer one supports
AVX2, while the older one supports AVX only.

I realize that this bug is actually a manifestation of #1524069, and has
more to do with Libvirt/QEMU than Nova, but it also looks like Nova
could be made to configure Libvirt in a way that would work around this
bug, which would be great.

Steps to reproduce
==================
* openstack server create --image ubuntu-1604-xenial --flavor m1.small --nic net-id=c418b807-55e0-4bcf-b31d-6206594a5311 foo

Expected result
===============
Have a functioning Xenial instance.

Actual result
=============
The instance crashes shortly after loading raid6:

Begin: Loading essential drivers ... [    3.549857] md: linear personality registered for level -1
[    3.554621] md: multipath personality registered for level -4
[    3.559487] md: raid0 personality registered for level 0
[    3.564545] md: raid1 personality registered for level 1
[    3.639509] raid6: sse2x1   gen()  6920 MB/s
[    3.707518] raid6: sse2x1   xor()  5781 MB/s
[    3.775508] raid6: sse2x2   gen()  9630 MB/s
[    3.843506] raid6: sse2x2   xor()  5438 MB/s
[    3.911506] raid6: sse2x4   gen() 11722 MB/s
[    3.979503] raid6: sse2x4   xor()  7960 MB/s
[    3.983515] invalid opcode: 0000 [#1] SMP 
[    3.984205] Modules linked in: raid6_pq(+) libcrc32c raid1 raid0 multipath linear psmouse floppy
[    3.985859] CPU: 0 PID: 230 Comm: modprobe Not tainted 4.4.0-21-generic #37-Ubuntu
[    3.986881] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Ubuntu-1.8.2-1ubuntu1~cloud0 04/01/2014
[    3.988118] task: ffff8800bb1d7080 ti: ffff8800b9a48000 task.ti: ffff8800b9a48000
[    3.989124] RIP: 0010:[<ffffffffc0061a8d>]  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
[    3.992121] RSP: 0018:ffff8800b9a4bb78  EFLAGS: 00010246
[    3.992808] RAX: 0000000000000000 RBX: ffff8800b9a4bbc8 RCX: 00000000fffedeae
[    3.993669] RDX: 0000000000000080 RSI: 0000000000001000 RDI: 0000000000000012
[    3.994541] RBP: ffff8800b9a4bba8 R08: 0000000000000000 R09: 00000000000001bd
[    3.995446] R10: 00000000fffede9d R11: 00000000000001bd R12: 0000000000001000
[    3.996307] R13: ffff8800bb022000 R14: ffff8800bb023000 R15: 0000000000000012
[    3.997167] FS:  00007fa2699f6700(0000) GS:ffff88013fc00000(0000) knlGS:0000000000000000
[    3.998245] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    3.998974] CR2: 000056292fa0b008 CR3: 00000000b9a19000 CR4: 00000000001006f0
[    3.999840] Stack:
[    4.000204]  0000000000000080 ffffffffc00747a0 0000000000000001 0000000000003fb0
[    4.001439]  ffffffffc0062238 ffff8800bb022000 ffff8800b9a4bc88 ffffffffc0079116
[    4.002684]  00000000fffedeae 0000000000002ee4 ffffffffc0064600 ffffffffc0065600
[    4.004020] Call Trace:
[    4.004429]  [<ffffffffc0079116>] init_module+0x116/0x1000 [raid6_pq]
[    4.005243]  [<ffffffffc0079000>] ? 0xffffffffc0079000
[    4.005917]  [<ffffffff81002123>] do_one_initcall+0xb3/0x200
[    4.006651]  [<ffffffff818205f8>] ? preempt_schedule_common+0x18/0x30
[    4.007451]  [<ffffffff8182062c>] ? _cond_resched+0x1c/0x30
[    4.008214]  [<ffffffff811eaeb3>] ? kmem_cache_alloc_trace+0x183/0x1f0
[    4.009021]  [<ffffffff8118c163>] do_init_module+0x5f/0x1cf
[    4.009734]  [<ffffffff81109df7>] load_module+0x1667/0x1c00
[    4.010458]  [<ffffffff811063a0>] ? __symbol_put+0x60/0x60
[    4.011163]  [<ffffffff812126b0>] ? kernel_read+0x50/0x80
[    4.011861]  [<ffffffff8110a5d4>] SYSC_finit_module+0xb4/0xe0
[    4.012590]  [<ffffffff8110a61e>] SyS_finit_module+0xe/0x10
[    4.013302]  [<ffffffff818244f2>] entry_SYSCALL_64_fastpath+0x16/0x71
[    4.014104] Code: 55 41 54 53 48 89 d3 48 8d 14 c5 00 00 00 00 41 89 ff 49 89 f4 48 83 ec 08 4c 8b 2c c3 4c 8b 74 13 08 48 89 55 d0 e8 53 83 fd c0 <c5> fd 6f 05 8b 2e 01 00 c5 e5 ef db 4d 85 e4 48 8b 55 d0 0f 84 
[    4.020068] RIP  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
[    4.023317]  RSP <ffff8800b9a4bb78>
[    4.023847] ---[ end trace b3853dc6e5fc1f8f ]---
Segmentation fault

Environment
===========
1. I'm running OpenStack Liberty:

ii  nova-common                          2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - common files
ii  nova-compute                         2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - compute node base
ii  nova-compute-kvm                     2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - compute node (KVM)
ii  nova-compute-libvirt                 2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - compute node libvirt support
ii  python-nova                          2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute Python libraries
ii  python-novaclient                    2:2.30.1-1~cloud0                     all          client library for OpenStack Compute API

2. I'm using Libvirt (1.2.16-2ubuntu11.15.10.3~cloud0) + KVM (1:2.3
+dfsg-5ubuntu9.2~cloud0)

3. I'm using Ceph 9.2.1-1trusty as a storage backend

4. I'm using Neutron with Openvswitch for networking

Logs & Configs
==============
Here's the full console log for an instance that crashes:

[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Initializing cgroup subsys cpuacct
[    0.000000] Linux version 4.4.0-21-generic (buildd@lgw01-21) (gcc version 5.3.1 20160413 (Ubuntu 5.3.1-14ubuntu2) ) #37-Ubuntu SMP Mon Apr 18 18:33:37 UTC 2016 (Ubuntu 4.4.0-21.37-generic 4.4.6)
[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic root=LABEL=cloudimg-rootfs ro console=tty1 console=ttyS0
[    0.000000] KERNEL supported cpus:
[    0.000000]   Intel GenuineIntel
[    0.000000]   AMD AuthenticAMD
[    0.000000]   Centaur CentaurHauls
[    0.000000] x86/fpu: Legacy x87 FPU detected.
[    0.000000] x86/fpu: Using 'lazy' FPU context switches.
[    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 0x0000000000100000-0x00000000bffdffff] usable
[    0.000000] BIOS-e820: [mem 0x00000000bffe0000-0x00000000bfffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000013fffffff] usable
[    0.000000] NX (Execute Disable) protection: active
[    0.000000] SMBIOS 2.8 present.
[    0.000000] Hypervisor detected: KVM
[    0.000000] e820: last_pfn = 0x140000 max_arch_pfn = 0x400000000
[    0.000000] x86/PAT: Configuration [0-7]: WB  WC  UC- UC  WB  WC  UC- WT  
[    0.000000] e820: last_pfn = 0xbffe0 max_arch_pfn = 0x400000000
[    0.000000] found SMP MP-table at [mem 0x000f6470-0x000f647f] mapped at [ffff8800000f6470]
[    0.000000] Scanning 1 areas for low memory corruption
[    0.000000] Using GB pages for direct mapping
[    0.000000] RAMDISK: [mem 0x371c6000-0x378dafff]
[    0.000000] ACPI: Early table checksum verification disabled
[    0.000000] ACPI: RSDP 0x00000000000F6240 000014 (v00 BOCHS )
[    0.000000] ACPI: RSDT 0x00000000BFFE1672 000030 (v01 BOCHS  BXPCRSDT 00000001 BXPC 00000001)
[    0.000000] ACPI: FACP 0x00000000BFFE0BDA 000074 (v01 BOCHS  BXPCFACP 00000001 BXPC 00000001)
[    0.000000] ACPI: DSDT 0x00000000BFFE0040 000B9A (v01 BOCHS  BXPCDSDT 00000001 BXPC 00000001)
[    0.000000] ACPI: FACS 0x00000000BFFE0000 000040
[    0.000000] ACPI: SSDT 0x00000000BFFE0C4E 0009AC (v01 BOCHS  BXPCSSDT 00000001 BXPC 00000001)
[    0.000000] ACPI: APIC 0x00000000BFFE15FA 000078 (v01 BOCHS  BXPCAPIC 00000001 BXPC 00000001)
[    0.000000] No NUMA configuration found
[    0.000000] Faking a node at [mem 0x0000000000000000-0x000000013fffffff]
[    0.000000] NODE_DATA(0) allocated [mem 0x13fff9000-0x13fffdfff]
[    0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00
[    0.000000] kvm-clock: cpu 0, msr 1:3fff5001, primary cpu clock
[    0.000000] kvm-clock: using sched offset of 1523727129 cycles
[    0.000000] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x0000000000001000-0x0000000000ffffff]
[    0.000000]   DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
[    0.000000]   Normal   [mem 0x0000000100000000-0x000000013fffffff]
[    0.000000]   Device   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000001000-0x000000000009efff]
[    0.000000]   node   0: [mem 0x0000000000100000-0x00000000bffdffff]
[    0.000000]   node   0: [mem 0x0000000100000000-0x000000013fffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000001000-0x000000013fffffff]
[    0.000000] ACPI: PM-Timer IO Port: 0x608
[    0.000000] ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1])
[    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] smpboot: Allowing 1 CPUs, 0 hotplug CPUs
[    0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    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] PM: Registered nosave memory: [mem 0xbffe0000-0xbfffffff]
[    0.000000] PM: Registered nosave memory: [mem 0xc0000000-0xfeffbfff]
[    0.000000] PM: Registered nosave memory: [mem 0xfeffc000-0xfeffffff]
[    0.000000] PM: Registered nosave memory: [mem 0xff000000-0xfffbffff]
[    0.000000] PM: Registered nosave memory: [mem 0xfffc0000-0xffffffff]
[    0.000000] e820: [mem 0xc0000000-0xfeffbfff] available for PCI devices
[    0.000000] Booting paravirtualized kernel on KVM
[    0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645519600211568 ns
[    0.000000] setup_percpu: NR_CPUS:256 nr_cpumask_bits:256 nr_cpu_ids:1 nr_node_ids:1
[    0.000000] PERCPU: Embedded 33 pages/cpu @ffff88013fc00000 s98008 r8192 d28968 u2097152
[    0.000000] KVM setup async PF for cpu 0
[    0.000000] kvm-stealtime: cpu 0, msr 13fc0d940
[    0.000000] Built 1 zonelists in Node order, mobility grouping on.  Total pages: 1032041
[    0.000000] Policy zone: Normal
[    0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic root=LABEL=cloudimg-rootfs ro console=tty1 console=ttyS0
[    0.000000] PID hash table entries: 4096 (order: 3, 32768 bytes)
[    0.000000] Memory: 4035988K/4193784K available (8356K kernel code, 1278K rwdata, 3920K rodata, 1476K init, 1292K bss, 157796K reserved, 0K cma-reserved)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[    0.000000] Hierarchical RCU implementation.
[    0.000000] 	Build-time adjustment of leaf fanout to 64.
[    0.000000] 	RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=1.
[    0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=1
[    0.000000] NR_IRQS:16640 nr_irqs:256 16
[    0.000000] Console: colour VGA+ 80x25
[    0.000000] console [tty1] enabled
[    0.000000] console [ttyS0] enabled
[    0.000000] tsc: Detected 2599.996 MHz processor
[    0.203234] Calibrating delay loop (skipped) preset value.. 5199.99 BogoMIPS (lpj=10399984)
[    0.205106] pid_max: default: 32768 minimum: 301
[    0.206149] ACPI: Core revision 20150930
[    0.208546] ACPI: 2 ACPI AML tables successfully acquired and loaded
[    0.210119] Security Framework initialized
[    0.211083] Yama: becoming mindful.
[    0.211892] AppArmor: AppArmor initialized
[    0.213706] Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes)
[    0.218689] Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes)
[    0.220490] Mount-cache hash table entries: 8192 (order: 4, 65536 bytes)
[    0.221766] Mountpoint-cache hash table entries: 8192 (order: 4, 65536 bytes)
[    0.223302] Initializing cgroup subsys io
[    0.224173] Initializing cgroup subsys memory
[    0.225039] Initializing cgroup subsys devices
[    0.225972] Initializing cgroup subsys freezer
[    0.226861] Initializing cgroup subsys net_cls
[    0.227736] Initializing cgroup subsys perf_event
[    0.228640] Initializing cgroup subsys net_prio
[    0.229564] Initializing cgroup subsys hugetlb
[    0.230503] Initializing cgroup subsys pids
[    0.231432] CPU: CPU feature xsave disabled, no CPUID level 0xd
[    0.233625] mce: CPU supports 10 MCE banks
[    0.234535] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
[    0.235488] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
[    0.250916] Freeing SMP alternatives memory: 28K (ffffffff820b2000 - ffffffff820b9000)
[    0.258620] ftrace: allocating 31878 entries in 125 pages
[    0.292291] smpboot: Max logical packages: 1
[    0.292979] smpboot: APIC(0) Converting physical 0 to logical package 0
[    0.294062] x2apic enabled
[    0.294775] Switched APIC routing to physical x2apic.
[    0.296242] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[    0.297081] smpboot: CPU0: Intel Core i7 9xx (Nehalem Class Core i7) (family: 0x6, model: 0x1a, stepping: 0x3)
[    0.298727] Performance Events: unsupported p6 CPU model 26 no PMU driver, software events only.
[    0.300782] x86: Booted up 1 node, 1 CPUs
[    0.301405] smpboot: Total of 1 processors activated (5199.99 BogoMIPS)
[    0.303089] devtmpfs: initialized
[    0.306053] evm: security.selinux
[    0.306590] evm: security.SMACK64
[    0.308354] evm: security.SMACK64EXEC
[    0.308915] evm: security.SMACK64TRANSMUTE
[    0.309542] evm: security.SMACK64MMAP
[    0.310113] evm: security.ima
[    0.310586] evm: security.capability
[    0.311236] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[    0.312590] pinctrl core: initialized pinctrl subsystem
[    0.313427] RTC time:  5:35:03, date: 05/04/16
[    0.315133] NET: Registered protocol family 16
[    0.315908] cpuidle: using governor ladder
[    0.316534] cpuidle: using governor menu
[    0.317108] PCCT header not found.
[    0.317686] ACPI: bus type PCI registered
[    0.318298] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
[    0.319192] PCI: Using configuration type 1 for base access
[    0.320935] ACPI: Added _OSI(Module Device)
[    0.321524] ACPI: Added _OSI(Processor Device)
[    0.322129] ACPI: Added _OSI(3.0 _SCP Extensions)
[    0.322761] ACPI: Added _OSI(Processor Aggregator Device)
[    0.324221] ACPI: Interpreter enabled
[    0.324764] ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [\_S1_] (20150930/hwxface-580)
[    0.326118] ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [\_S2_] (20150930/hwxface-580)
[    0.327447] ACPI: (supports S0 S3 S4 S5)
[    0.328000] ACPI: Using IOAPIC for interrupt routing
[    0.328670] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug
[    0.331711] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
[    0.332501] acpi PNP0A03:00: _OSC: OS supports [ASPM ClockPM Segments MSI]
[    0.333346] acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM
[    0.334219] acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended PCI configuration space under this bridge.
[    0.335856] acpiphp: Slot [3] registered
[    0.336431] acpiphp: Slot [4] registered
[    0.336997] acpiphp: Slot [5] registered
[    0.337563] acpiphp: Slot [6] registered
[    0.339449] acpiphp: Slot [7] registered
[    0.348585] acpiphp: Slot [8] registered
[    0.349160] acpiphp: Slot [9] registered
[    0.349731] acpiphp: Slot [10] registered
[    0.350315] acpiphp: Slot [11] registered
[    0.350891] acpiphp: Slot [12] registered
[    0.351465] acpiphp: Slot [13] registered
[    0.352053] acpiphp: Slot [14] registered
[    0.352637] acpiphp: Slot [15] registered
[    0.353224] acpiphp: Slot [16] registered
[    0.353799] acpiphp: Slot [17] registered
[    0.354382] acpiphp: Slot [18] registered
[    0.354956] acpiphp: Slot [19] registered
[    0.355533] acpiphp: Slot [20] registered
[    0.356105] acpiphp: Slot [21] registered
[    0.356686] acpiphp: Slot [22] registered
[    0.357261] acpiphp: Slot [23] registered
[    0.357834] acpiphp: Slot [24] registered
[    0.358500] acpiphp: Slot [25] registered
[    0.359114] acpiphp: Slot [26] registered
[    0.359721] acpiphp: Slot [27] registered
[    0.360294] acpiphp: Slot [28] registered
[    0.360884] acpiphp: Slot [29] registered
[    0.361463] acpiphp: Slot [30] registered
[    0.362061] acpiphp: Slot [31] registered
[    0.362640] PCI host bridge to bus 0000:00
[    0.363218] pci_bus 0000:00: root bus resource [io  0x0000-0x0cf7 window]
[    0.364054] pci_bus 0000:00: root bus resource [io  0x0d00-0xffff window]
[    0.364895] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff window]
[    0.365913] pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window]
[    0.366933] pci_bus 0000:00: root bus resource [bus 00-ff]
[    0.377218] pci 0000:00:01.1: legacy IDE quirk: reg 0x10: [io  0x01f0-0x01f7]
[    0.378115] pci 0000:00:01.1: legacy IDE quirk: reg 0x14: [io  0x03f6]
[    0.379563] pci 0000:00:01.1: legacy IDE quirk: reg 0x18: [io  0x0170-0x0177]
[    0.380477] pci 0000:00:01.1: legacy IDE quirk: reg 0x1c: [io  0x0376]
[    0.387873] pci 0000:00:01.3: quirk: [io  0x0600-0x063f] claimed by PIIX4 ACPI
[    0.388875] pci 0000:00:01.3: quirk: [io  0x0700-0x070f] claimed by PIIX4 SMB
[    0.465906] ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11)
[    0.467014] ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11)
[    0.468064] ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11)
[    0.469125] ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11)
[    0.471532] ACPI: PCI Interrupt Link [LNKS] (IRQs *9)
[    0.472585] ACPI: Enabled 16 GPEs in block 00 to 0F
[    0.473485] vgaarb: setting as boot device: PCI:0000:00:02.0
[    0.474215] vgaarb: device added: PCI:0000:00:02.0,decodes=io+mem,owns=io+mem,locks=none
[    0.475270] vgaarb: loaded
[    0.475696] vgaarb: bridge control possible 0000:00:02.0
[    0.476672] SCSI subsystem initialized
[    0.477271] ACPI: bus type USB registered
[    0.477860] usbcore: registered new interface driver usbfs
[    0.478614] usbcore: registered new interface driver hub
[    0.479309] usbcore: registered new device driver usb
[    0.480158] PCI: Using ACPI for IRQ routing
[    0.480957] NetLabel: Initializing
[    0.481458] NetLabel:  domain hash size = 128
[    0.482057] NetLabel:  protocols = UNLABELED CIPSOv4
[    0.482716] NetLabel:  unlabeled traffic allowed by default
[    0.483498] clocksource: Switched to clocksource kvm-clock
[    0.490934] AppArmor: AppArmor Filesystem Enabled
[    0.491635] pnp: PnP ACPI init
[    0.492436] pnp: PnP ACPI: found 6 devices
[    0.500252] clocksource: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: 2085701024 ns
[    0.501486] NET: Registered protocol family 2
[    0.502247] TCP established hash table entries: 32768 (order: 6, 262144 bytes)
[    0.503283] TCP bind hash table entries: 32768 (order: 7, 524288 bytes)
[    0.504146] TCP: Hash tables configured (established 32768 bind 32768)
[    0.504963] UDP hash table entries: 2048 (order: 4, 65536 bytes)
[    0.505719] UDP-Lite hash table entries: 2048 (order: 4, 65536 bytes)
[    0.506557] NET: Registered protocol family 1
[    0.507157] pci 0000:00:00.0: Limiting direct PCI/PCI transfers
[    0.507914] pci 0000:00:01.0: PIIX3: Enabling Passive Release
[    0.508646] pci 0000:00:01.0: Activating ISA DMA hang workarounds
[    0.510002] Trying to unpack rootfs image as initramfs...
[    1.717098] Freeing initrd memory: 7252K (ffff8800371c6000 - ffff8800378db000)
[    1.718412] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
[    1.719192] software IO TLB [mem 0xbbfe0000-0xbffe0000] (64MB) mapped at [ffff8800bbfe0000-ffff8800bffdffff]
[    1.725831] Scanning for low memory corruption every 60 seconds
[    1.731157] futex hash table entries: 256 (order: 2, 16384 bytes)
[    1.731891] audit: initializing netlink subsys (disabled)
[    1.732583] audit: type=2000 audit(1462340105.446:1): initialized
[    1.733541] Initialise system trusted keyring
[    1.734188] HugeTLB registered 1 GB page size, pre-allocated 0 pages
[    1.734913] HugeTLB registered 2 MB page size, pre-allocated 0 pages
[    1.736700] zbud: loaded
[    1.737254] VFS: Disk quotas dquot_6.6.0
[    1.737797] VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[    1.738984] fuse init (API version 7.23)
[    1.739650] Key type big_key registered
[    1.740289] Key type asymmetric registered
[    1.740823] Asymmetric key parser 'x509' registered
[    1.741422] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 249)
[    1.742418] io scheduler noop registered
[    1.742951] io scheduler deadline registered (default)
[    1.743580] io scheduler cfq registered
[    1.744138] pci_hotplug: PCI Hot Plug PCI Core version: 0.5
[    1.744813] pciehp: PCI Express Hot Plug Controller Driver version: 0.4
[    1.745653] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input0
[    1.746619] ACPI: Power Button [PWRF]
[    1.747193] GHES: HEST is not enabled!
[    1.763884] ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 11
[    1.764640] virtio-pci 0000:00:03.0: virtio_pci: leaving for legacy driver
[    1.782055] ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 10
[    1.782747] virtio-pci 0000:00:04.0: virtio_pci: leaving for legacy driver
[    1.799998] ACPI: PCI Interrupt Link [LNKA] enabled at IRQ 10
[    1.800665] virtio-pci 0000:00:05.0: virtio_pci: leaving for legacy driver
[    1.817293] ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 11
[    1.817943] virtio-pci 0000:00:06.0: virtio_pci: leaving for legacy driver
[    1.819651] Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled
[    1.842639] 00:04: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
[    1.866310] 00:05: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
[    1.887604] Linux agpgart interface v0.103
[    1.889620] brd: module loaded
[    1.890749] loop: module loaded
[    1.908069]  vda: vda1
[    1.909586] scsi host0: ata_piix
[    1.910066] scsi host1: ata_piix
[    1.910562] ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc0e0 irq 14
[    1.911256] ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc0e8 irq 15
[    1.912214] libphy: Fixed MDIO Bus: probed
[    1.912753] tun: Universal TUN/TAP device driver, 1.6
[    1.913312] tun: (C) 1999-2004 Max Krasnyansky <maxk@xxxxxxxxxxxx>
[    1.930649] PPP generic driver version 2.4.2
[    1.931288] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[    1.932010] ehci-pci: EHCI PCI platform driver
[    1.932597] ehci-platform: EHCI generic platform driver
[    1.933234] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[    1.933950] ohci-pci: OHCI PCI platform driver
[    1.934539] ohci-platform: OHCI generic platform driver
[    1.935191] uhci_hcd: USB Universal Host Controller Interface driver
[    1.952374] uhci_hcd 0000:00:01.2: UHCI Host Controller
[    1.953034] uhci_hcd 0000:00:01.2: new USB bus registered, assigned bus number 1
[    1.953952] uhci_hcd 0000:00:01.2: detected 2 ports
[    1.954651] uhci_hcd 0000:00:01.2: irq 10, io base 0x0000c040
[    1.955379] usb usb1: New USB device found, idVendor=1d6b, idProduct=0001
[    1.956168] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[    1.957139] usb usb1: Product: UHCI Host Controller
[    1.957768] usb usb1: Manufacturer: Linux 4.4.0-21-generic uhci_hcd
[    1.958543] usb usb1: SerialNumber: 0000:00:01.2
[    1.959264] hub 1-0:1.0: USB hub found
[    1.959936] hub 1-0:1.0: 2 ports detected
[    1.960616] i8042: PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12
[    1.962228] serio: i8042 KBD port at 0x60,0x64 irq 1
[    1.962900] serio: i8042 AUX port at 0x60,0x64 irq 12
[    1.963656] mousedev: PS/2 mouse device common for all mice
[    1.964524] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input1
[    1.965802] rtc_cmos 00:00: RTC can wake from S4
[    1.966583] rtc_cmos 00:00: rtc core: registered rtc_cmos as rtc0
[    1.967397] rtc_cmos 00:00: alarms up to one day, 114 bytes nvram
[    1.968119] i2c /dev entries driver
[    1.968702] device-mapper: uevent: version 1.0.3
[    1.969336] device-mapper: ioctl: 4.34.0-ioctl (2015-10-28) initialised: dm-devel@xxxxxxxxxx
[    1.970428] ledtrig-cpu: registered to indicate activity on CPUs
[    1.971346] NET: Registered protocol family 10
[    1.972135] NET: Registered protocol family 17
[    1.972732] Key type dns_resolver registered
[    1.973409] microcode: CPU0 sig=0x106a3, pf=0x1, revision=0x1
[    1.974182] microcode: Microcode Update Driver: v2.01 <tigran@xxxxxxxxxxxxxxxxxxxx>, Peter Oruba
[    1.975389] registered taskstats version 1
[    1.975957] Loading compiled-in X.509 certificates
[    1.977206] Loaded X.509 cert 'Build time autogenerated kernel key: fc7c0e9f152f32eca50ea2d9722926e5127af244'
[    1.978456] zswap: loaded using pool lzo/zbud
[    1.980197] Key type trusted registered
[    1.992720] Key type encrypted registered
[    1.993250] AppArmor: AppArmor sha1 policy hashing enabled
[    1.993898] ima: No TPM chip found, activating TPM-bypass!
[    1.994625] evm: HMAC attrs: 0x1
[    1.995271]   Magic number: 0:849:566
[    1.995909] rtc_cmos 00:00: setting system clock to 2016-05-04 05:35:05 UTC (1462340105)
[    1.997035] BIOS EDD facility v0.16 2004-Jun-25, 0 devices found
[    1.997702] EDD information not available.
[    2.073644] Freeing unused kernel memory: 1476K (ffffffff81f41000 - ffffffff820b2000)
[    2.075469] Write protecting the kernel read-only data: 14336k
[    2.077486] Freeing unused kernel memory: 1872K (ffff88000182c000 - ffff880001a00000)
[    2.079999] Freeing unused kernel memory: 176K (ffff880001dd4000 - ffff880001e00000)
Loading, please wait...
starting version 229
[    2.095265] random: udevadm urandom read with 2 bits of entropy available
[    2.140733] virtio_net virtio0 ens3: renamed from eth0
[    2.148962] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input4
[    2.150419] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input3
[    2.179873] FDC 0 is a S82078B
[    2.723675] tsc: Refined TSC clocksource calibration: 2600.056 MHz
[    2.725415] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x257a71592ee, max_idle_ns: 440795334892 ns
Begin: Loading essential drivers ... [    3.549857] md: linear personality registered for level -1
[    3.554621] md: multipath personality registered for level -4
[    3.559487] md: raid0 personality registered for level 0
[    3.564545] md: raid1 personality registered for level 1
[    3.639509] raid6: sse2x1   gen()  6920 MB/s
[    3.707518] raid6: sse2x1   xor()  5781 MB/s
[    3.775508] raid6: sse2x2   gen()  9630 MB/s
[    3.843506] raid6: sse2x2   xor()  5438 MB/s
[    3.911506] raid6: sse2x4   gen() 11722 MB/s
[    3.979503] raid6: sse2x4   xor()  7960 MB/s
[    3.983515] invalid opcode: 0000 [#1] SMP 
[    3.984205] Modules linked in: raid6_pq(+) libcrc32c raid1 raid0 multipath linear psmouse floppy
[    3.985859] CPU: 0 PID: 230 Comm: modprobe Not tainted 4.4.0-21-generic #37-Ubuntu
[    3.986881] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Ubuntu-1.8.2-1ubuntu1~cloud0 04/01/2014
[    3.988118] task: ffff8800bb1d7080 ti: ffff8800b9a48000 task.ti: ffff8800b9a48000
[    3.989124] RIP: 0010:[<ffffffffc0061a8d>]  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
[    3.992121] RSP: 0018:ffff8800b9a4bb78  EFLAGS: 00010246
[    3.992808] RAX: 0000000000000000 RBX: ffff8800b9a4bbc8 RCX: 00000000fffedeae
[    3.993669] RDX: 0000000000000080 RSI: 0000000000001000 RDI: 0000000000000012
[    3.994541] RBP: ffff8800b9a4bba8 R08: 0000000000000000 R09: 00000000000001bd
[    3.995446] R10: 00000000fffede9d R11: 00000000000001bd R12: 0000000000001000
[    3.996307] R13: ffff8800bb022000 R14: ffff8800bb023000 R15: 0000000000000012
[    3.997167] FS:  00007fa2699f6700(0000) GS:ffff88013fc00000(0000) knlGS:0000000000000000
[    3.998245] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    3.998974] CR2: 000056292fa0b008 CR3: 00000000b9a19000 CR4: 00000000001006f0
[    3.999840] Stack:
[    4.000204]  0000000000000080 ffffffffc00747a0 0000000000000001 0000000000003fb0
[    4.001439]  ffffffffc0062238 ffff8800bb022000 ffff8800b9a4bc88 ffffffffc0079116
[    4.002684]  00000000fffedeae 0000000000002ee4 ffffffffc0064600 ffffffffc0065600
[    4.004020] Call Trace:
[    4.004429]  [<ffffffffc0079116>] init_module+0x116/0x1000 [raid6_pq]
[    4.005243]  [<ffffffffc0079000>] ? 0xffffffffc0079000
[    4.005917]  [<ffffffff81002123>] do_one_initcall+0xb3/0x200
[    4.006651]  [<ffffffff818205f8>] ? preempt_schedule_common+0x18/0x30
[    4.007451]  [<ffffffff8182062c>] ? _cond_resched+0x1c/0x30
[    4.008214]  [<ffffffff811eaeb3>] ? kmem_cache_alloc_trace+0x183/0x1f0
[    4.009021]  [<ffffffff8118c163>] do_init_module+0x5f/0x1cf
[    4.009734]  [<ffffffff81109df7>] load_module+0x1667/0x1c00
[    4.010458]  [<ffffffff811063a0>] ? __symbol_put+0x60/0x60
[    4.011163]  [<ffffffff812126b0>] ? kernel_read+0x50/0x80
[    4.011861]  [<ffffffff8110a5d4>] SYSC_finit_module+0xb4/0xe0
[    4.012590]  [<ffffffff8110a61e>] SyS_finit_module+0xe/0x10
[    4.013302]  [<ffffffff818244f2>] entry_SYSCALL_64_fastpath+0x16/0x71
[    4.014104] Code: 55 41 54 53 48 89 d3 48 8d 14 c5 00 00 00 00 41 89 ff 49 89 f4 48 83 ec 08 4c 8b 2c c3 4c 8b 74 13 08 48 89 55 d0 e8 53 83 fd c0 <c5> fd 6f 05 8b 2e 01 00 c5 e5 ef db 4d 85 e4 48 8b 55 d0 0f 84 
[    4.020068] RIP  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
[    4.023317]  RSP <ffff8800b9a4bb78>
[    4.023847] ---[ end trace b3853dc6e5fc1f8f ]---
Segmentation fault

And here's the corresponding Libvirt XML:

<domain type='kvm' id='411'>
  <name>instance-000030cd</name>
  <uuid>587a3497-3198-4c19-87c4-ddf449385f71</uuid>
  <metadata>
    <nova:instance xmlns:nova="http://openstack.org/xmlns/libvirt/nova/1.0";>
      <nova:package version="12.0.1"/>
      <nova:name>test-xenial-segfault</nova:name>
      <nova:creationTime>2016-05-04 05:39:55</nova:creationTime>
      <nova:flavor name="m1.small">
        <nova:memory>4096</nova:memory>
        <nova:disk>16</nova:disk>
        <nova:swap>0</nova:swap>
        <nova:ephemeral>0</nova:ephemeral>
        <nova:vcpus>1</nova:vcpus>
      </nova:flavor>
      <nova:owner>
        <nova:user uuid="07d961b93aed45c0b7989f91c40341ae">username</nova:user>
        <nova:project uuid="dd4f48116bd942f9b145d20e9f1a11be">project</nova:project>
      </nova:owner>
      <nova:root type="image" uuid="4b5b61a5-008c-4424-a899-f6896384a55c"/>
    </nova:instance>
  </metadata>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <cputune>
    <shares>1024</shares>
  </cputune>
  <resource>
    <partition>/machine</partition>
  </resource>
  <sysinfo type='smbios'>
    <system>
      <entry name='manufacturer'>OpenStack Foundation</entry>
      <entry name='product'>OpenStack Nova</entry>
      <entry name='version'>12.0.1</entry>
      <entry name='serial'>00000000-0000-0000-0000-0cc47a349290</entry>
      <entry name='uuid'>587a3497-3198-4c19-87c4-ddf449385f71</entry>
      <entry name='family'>Virtual Machine</entry>
    </system>
  </sysinfo>
  <os>
    <type arch='x86_64' machine='pc-i440fx-vivid'>hvm</type>
    <boot dev='hd'/>
    <smbios mode='sysinfo'/>
  </os>
  <features>
    <acpi/>
    <apic/>
  </features>
  <cpu mode='host-model'>
    <model fallback='allow'/>
    <topology sockets='1' cores='1' threads='1'/>
  </cpu>
  <clock offset='utc'>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <disk type='network' device='disk'>
      <driver name='qemu' type='raw' cache='writeback'/>
      <auth username='cinder'>
        <secret type='ceph' uuid='23c33478-af4c-49d0-bb46-9890d6b89084'/>
      </auth>
      <source protocol='rbd' name='libvirt/587a3497-3198-4c19-87c4-ddf449385f71_disk'>
        <host name='172.24.3.17' port='6789'/>
        <host name='172.24.3.18' port='6789'/>
        <host name='172.24.3.19' port='6789'/>
        <host name='172.24.3.25' port='6789'/>
        <host name='172.24.3.26' port='6789'/>
      </source>
      <backingStore/>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </disk>
    <controller type='usb' index='0'>
      <alias name='usb'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'>
      <alias name='pci.0'/>
    </controller>
    <controller type='virtio-serial' index='0'>
      <alias name='virtio-serial0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </controller>
    <interface type='bridge'>
      <mac address='fa:16:3e:3c:5e:88'/>
      <source bridge='qbrba81b423-ab'/>
      <target dev='tapba81b423-ab'/>
      <model type='virtio'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='file'>
      <source path='/var/lib/nova/instances/587a3497-3198-4c19-87c4-ddf449385f71/console.log'/>
      <target port='0'/>
      <alias name='serial0'/>
    </serial>
    <serial type='pty'>
      <source path='/dev/pts/34'/>
      <target port='1'/>
      <alias name='serial1'/>
    </serial>
    <console type='file'>
      <source path='/var/lib/nova/instances/587a3497-3198-4c19-87c4-ddf449385f71/console.log'/>
      <target type='serial' port='0'/>
      <alias name='serial0'/>
    </console>
    <channel type='pty'>
      <source path='/dev/pts/35'/>
      <target type='virtio' name='com.redhat.spice.0' state='disconnected'/>
      <alias name='channel0'/>
      <address type='virtio-serial' controller='0' bus='0' port='1'/>
    </channel>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <graphics type='spice' port='5915' autoport='yes' listen='172.24.1.35' keymap='fr-ch'>
      <listen type='address' address='172.24.1.35'/>
    </graphics>
    <video>
      <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1'/>
      <alias name='video0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <stats period='10'/>
      <alias name='balloon0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </memballoon>
  </devices>
  <seclabel type='dynamic' model='apparmor' relabel='yes'>
    <label>libvirt-587a3497-3198-4c19-87c4-ddf449385f71</label>
    <imagelabel>libvirt-587a3497-3198-4c19-87c4-ddf449385f71</imagelabel>
  </seclabel>
</domain>

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1578079

Title:
  Ubuntu Xenial guests segfault on hosts with CPUs supporting AVX2

Status in OpenStack Compute (nova):
  New

Bug description:
  Description
  ===========
  When creating an Ubuntu Xenial instance from the official cloud image (https://cloud-images.ubuntu.com/xenial/current/), I noticed that sometimes it would boot just fine, sometimes it would crash almost immediately with a segmentation fault. After some investigation, I noticed that Xenial guest were crashing when running on my more recent hypervisors (Intel(R) Xeon(R) CPU E5-2660 v3 @ 2.60GHz), while they would run just fine on my older hypervisors (Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz).

  The difference between those two CPUs is that the newer one supports
  AVX2, while the older one supports AVX only.

  I realize that this bug is actually a manifestation of #1524069, and
  has more to do with Libvirt/QEMU than Nova, but it also looks like
  Nova could be made to configure Libvirt in a way that would work
  around this bug, which would be great.

  Steps to reproduce
  ==================
  * openstack server create --image ubuntu-1604-xenial --flavor m1.small --nic net-id=c418b807-55e0-4bcf-b31d-6206594a5311 foo

  Expected result
  ===============
  Have a functioning Xenial instance.

  Actual result
  =============
  The instance crashes shortly after loading raid6:

  Begin: Loading essential drivers ... [    3.549857] md: linear personality registered for level -1
  [    3.554621] md: multipath personality registered for level -4
  [    3.559487] md: raid0 personality registered for level 0
  [    3.564545] md: raid1 personality registered for level 1
  [    3.639509] raid6: sse2x1   gen()  6920 MB/s
  [    3.707518] raid6: sse2x1   xor()  5781 MB/s
  [    3.775508] raid6: sse2x2   gen()  9630 MB/s
  [    3.843506] raid6: sse2x2   xor()  5438 MB/s
  [    3.911506] raid6: sse2x4   gen() 11722 MB/s
  [    3.979503] raid6: sse2x4   xor()  7960 MB/s
  [    3.983515] invalid opcode: 0000 [#1] SMP 
  [    3.984205] Modules linked in: raid6_pq(+) libcrc32c raid1 raid0 multipath linear psmouse floppy
  [    3.985859] CPU: 0 PID: 230 Comm: modprobe Not tainted 4.4.0-21-generic #37-Ubuntu
  [    3.986881] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Ubuntu-1.8.2-1ubuntu1~cloud0 04/01/2014
  [    3.988118] task: ffff8800bb1d7080 ti: ffff8800b9a48000 task.ti: ffff8800b9a48000
  [    3.989124] RIP: 0010:[<ffffffffc0061a8d>]  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
  [    3.992121] RSP: 0018:ffff8800b9a4bb78  EFLAGS: 00010246
  [    3.992808] RAX: 0000000000000000 RBX: ffff8800b9a4bbc8 RCX: 00000000fffedeae
  [    3.993669] RDX: 0000000000000080 RSI: 0000000000001000 RDI: 0000000000000012
  [    3.994541] RBP: ffff8800b9a4bba8 R08: 0000000000000000 R09: 00000000000001bd
  [    3.995446] R10: 00000000fffede9d R11: 00000000000001bd R12: 0000000000001000
  [    3.996307] R13: ffff8800bb022000 R14: ffff8800bb023000 R15: 0000000000000012
  [    3.997167] FS:  00007fa2699f6700(0000) GS:ffff88013fc00000(0000) knlGS:0000000000000000
  [    3.998245] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [    3.998974] CR2: 000056292fa0b008 CR3: 00000000b9a19000 CR4: 00000000001006f0
  [    3.999840] Stack:
  [    4.000204]  0000000000000080 ffffffffc00747a0 0000000000000001 0000000000003fb0
  [    4.001439]  ffffffffc0062238 ffff8800bb022000 ffff8800b9a4bc88 ffffffffc0079116
  [    4.002684]  00000000fffedeae 0000000000002ee4 ffffffffc0064600 ffffffffc0065600
  [    4.004020] Call Trace:
  [    4.004429]  [<ffffffffc0079116>] init_module+0x116/0x1000 [raid6_pq]
  [    4.005243]  [<ffffffffc0079000>] ? 0xffffffffc0079000
  [    4.005917]  [<ffffffff81002123>] do_one_initcall+0xb3/0x200
  [    4.006651]  [<ffffffff818205f8>] ? preempt_schedule_common+0x18/0x30
  [    4.007451]  [<ffffffff8182062c>] ? _cond_resched+0x1c/0x30
  [    4.008214]  [<ffffffff811eaeb3>] ? kmem_cache_alloc_trace+0x183/0x1f0
  [    4.009021]  [<ffffffff8118c163>] do_init_module+0x5f/0x1cf
  [    4.009734]  [<ffffffff81109df7>] load_module+0x1667/0x1c00
  [    4.010458]  [<ffffffff811063a0>] ? __symbol_put+0x60/0x60
  [    4.011163]  [<ffffffff812126b0>] ? kernel_read+0x50/0x80
  [    4.011861]  [<ffffffff8110a5d4>] SYSC_finit_module+0xb4/0xe0
  [    4.012590]  [<ffffffff8110a61e>] SyS_finit_module+0xe/0x10
  [    4.013302]  [<ffffffff818244f2>] entry_SYSCALL_64_fastpath+0x16/0x71
  [    4.014104] Code: 55 41 54 53 48 89 d3 48 8d 14 c5 00 00 00 00 41 89 ff 49 89 f4 48 83 ec 08 4c 8b 2c c3 4c 8b 74 13 08 48 89 55 d0 e8 53 83 fd c0 <c5> fd 6f 05 8b 2e 01 00 c5 e5 ef db 4d 85 e4 48 8b 55 d0 0f 84 
  [    4.020068] RIP  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
  [    4.023317]  RSP <ffff8800b9a4bb78>
  [    4.023847] ---[ end trace b3853dc6e5fc1f8f ]---
  Segmentation fault

  Environment
  ===========
  1. I'm running OpenStack Liberty:

  ii  nova-common                          2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - common files
  ii  nova-compute                         2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - compute node base
  ii  nova-compute-kvm                     2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - compute node (KVM)
  ii  nova-compute-libvirt                 2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute - compute node libvirt support
  ii  python-nova                          2:12.0.1-0ubuntu1~cloud0              all          OpenStack Compute Python libraries
  ii  python-novaclient                    2:2.30.1-1~cloud0                     all          client library for OpenStack Compute API

  2. I'm using Libvirt (1.2.16-2ubuntu11.15.10.3~cloud0) + KVM (1:2.3
  +dfsg-5ubuntu9.2~cloud0)

  3. I'm using Ceph 9.2.1-1trusty as a storage backend

  4. I'm using Neutron with Openvswitch for networking

  Logs & Configs
  ==============
  Here's the full console log for an instance that crashes:

  [    0.000000] Initializing cgroup subsys cpuset
  [    0.000000] Initializing cgroup subsys cpu
  [    0.000000] Initializing cgroup subsys cpuacct
  [    0.000000] Linux version 4.4.0-21-generic (buildd@lgw01-21) (gcc version 5.3.1 20160413 (Ubuntu 5.3.1-14ubuntu2) ) #37-Ubuntu SMP Mon Apr 18 18:33:37 UTC 2016 (Ubuntu 4.4.0-21.37-generic 4.4.6)
  [    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic root=LABEL=cloudimg-rootfs ro console=tty1 console=ttyS0
  [    0.000000] KERNEL supported cpus:
  [    0.000000]   Intel GenuineIntel
  [    0.000000]   AMD AuthenticAMD
  [    0.000000]   Centaur CentaurHauls
  [    0.000000] x86/fpu: Legacy x87 FPU detected.
  [    0.000000] x86/fpu: Using 'lazy' FPU context switches.
  [    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 0x0000000000100000-0x00000000bffdffff] usable
  [    0.000000] BIOS-e820: [mem 0x00000000bffe0000-0x00000000bfffffff] reserved
  [    0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved
  [    0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved
  [    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000013fffffff] usable
  [    0.000000] NX (Execute Disable) protection: active
  [    0.000000] SMBIOS 2.8 present.
  [    0.000000] Hypervisor detected: KVM
  [    0.000000] e820: last_pfn = 0x140000 max_arch_pfn = 0x400000000
  [    0.000000] x86/PAT: Configuration [0-7]: WB  WC  UC- UC  WB  WC  UC- WT  
  [    0.000000] e820: last_pfn = 0xbffe0 max_arch_pfn = 0x400000000
  [    0.000000] found SMP MP-table at [mem 0x000f6470-0x000f647f] mapped at [ffff8800000f6470]
  [    0.000000] Scanning 1 areas for low memory corruption
  [    0.000000] Using GB pages for direct mapping
  [    0.000000] RAMDISK: [mem 0x371c6000-0x378dafff]
  [    0.000000] ACPI: Early table checksum verification disabled
  [    0.000000] ACPI: RSDP 0x00000000000F6240 000014 (v00 BOCHS )
  [    0.000000] ACPI: RSDT 0x00000000BFFE1672 000030 (v01 BOCHS  BXPCRSDT 00000001 BXPC 00000001)
  [    0.000000] ACPI: FACP 0x00000000BFFE0BDA 000074 (v01 BOCHS  BXPCFACP 00000001 BXPC 00000001)
  [    0.000000] ACPI: DSDT 0x00000000BFFE0040 000B9A (v01 BOCHS  BXPCDSDT 00000001 BXPC 00000001)
  [    0.000000] ACPI: FACS 0x00000000BFFE0000 000040
  [    0.000000] ACPI: SSDT 0x00000000BFFE0C4E 0009AC (v01 BOCHS  BXPCSSDT 00000001 BXPC 00000001)
  [    0.000000] ACPI: APIC 0x00000000BFFE15FA 000078 (v01 BOCHS  BXPCAPIC 00000001 BXPC 00000001)
  [    0.000000] No NUMA configuration found
  [    0.000000] Faking a node at [mem 0x0000000000000000-0x000000013fffffff]
  [    0.000000] NODE_DATA(0) allocated [mem 0x13fff9000-0x13fffdfff]
  [    0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00
  [    0.000000] kvm-clock: cpu 0, msr 1:3fff5001, primary cpu clock
  [    0.000000] kvm-clock: using sched offset of 1523727129 cycles
  [    0.000000] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns
  [    0.000000] Zone ranges:
  [    0.000000]   DMA      [mem 0x0000000000001000-0x0000000000ffffff]
  [    0.000000]   DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
  [    0.000000]   Normal   [mem 0x0000000100000000-0x000000013fffffff]
  [    0.000000]   Device   empty
  [    0.000000] Movable zone start for each node
  [    0.000000] Early memory node ranges
  [    0.000000]   node   0: [mem 0x0000000000001000-0x000000000009efff]
  [    0.000000]   node   0: [mem 0x0000000000100000-0x00000000bffdffff]
  [    0.000000]   node   0: [mem 0x0000000100000000-0x000000013fffffff]
  [    0.000000] Initmem setup node 0 [mem 0x0000000000001000-0x000000013fffffff]
  [    0.000000] ACPI: PM-Timer IO Port: 0x608
  [    0.000000] ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1])
  [    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] smpboot: Allowing 1 CPUs, 0 hotplug CPUs
  [    0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
  [    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] PM: Registered nosave memory: [mem 0xbffe0000-0xbfffffff]
  [    0.000000] PM: Registered nosave memory: [mem 0xc0000000-0xfeffbfff]
  [    0.000000] PM: Registered nosave memory: [mem 0xfeffc000-0xfeffffff]
  [    0.000000] PM: Registered nosave memory: [mem 0xff000000-0xfffbffff]
  [    0.000000] PM: Registered nosave memory: [mem 0xfffc0000-0xffffffff]
  [    0.000000] e820: [mem 0xc0000000-0xfeffbfff] available for PCI devices
  [    0.000000] Booting paravirtualized kernel on KVM
  [    0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645519600211568 ns
  [    0.000000] setup_percpu: NR_CPUS:256 nr_cpumask_bits:256 nr_cpu_ids:1 nr_node_ids:1
  [    0.000000] PERCPU: Embedded 33 pages/cpu @ffff88013fc00000 s98008 r8192 d28968 u2097152
  [    0.000000] KVM setup async PF for cpu 0
  [    0.000000] kvm-stealtime: cpu 0, msr 13fc0d940
  [    0.000000] Built 1 zonelists in Node order, mobility grouping on.  Total pages: 1032041
  [    0.000000] Policy zone: Normal
  [    0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic root=LABEL=cloudimg-rootfs ro console=tty1 console=ttyS0
  [    0.000000] PID hash table entries: 4096 (order: 3, 32768 bytes)
  [    0.000000] Memory: 4035988K/4193784K available (8356K kernel code, 1278K rwdata, 3920K rodata, 1476K init, 1292K bss, 157796K reserved, 0K cma-reserved)
  [    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
  [    0.000000] Hierarchical RCU implementation.
  [    0.000000] 	Build-time adjustment of leaf fanout to 64.
  [    0.000000] 	RCU restricting CPUs from NR_CPUS=256 to nr_cpu_ids=1.
  [    0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=1
  [    0.000000] NR_IRQS:16640 nr_irqs:256 16
  [    0.000000] Console: colour VGA+ 80x25
  [    0.000000] console [tty1] enabled
  [    0.000000] console [ttyS0] enabled
  [    0.000000] tsc: Detected 2599.996 MHz processor
  [    0.203234] Calibrating delay loop (skipped) preset value.. 5199.99 BogoMIPS (lpj=10399984)
  [    0.205106] pid_max: default: 32768 minimum: 301
  [    0.206149] ACPI: Core revision 20150930
  [    0.208546] ACPI: 2 ACPI AML tables successfully acquired and loaded
  [    0.210119] Security Framework initialized
  [    0.211083] Yama: becoming mindful.
  [    0.211892] AppArmor: AppArmor initialized
  [    0.213706] Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes)
  [    0.218689] Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes)
  [    0.220490] Mount-cache hash table entries: 8192 (order: 4, 65536 bytes)
  [    0.221766] Mountpoint-cache hash table entries: 8192 (order: 4, 65536 bytes)
  [    0.223302] Initializing cgroup subsys io
  [    0.224173] Initializing cgroup subsys memory
  [    0.225039] Initializing cgroup subsys devices
  [    0.225972] Initializing cgroup subsys freezer
  [    0.226861] Initializing cgroup subsys net_cls
  [    0.227736] Initializing cgroup subsys perf_event
  [    0.228640] Initializing cgroup subsys net_prio
  [    0.229564] Initializing cgroup subsys hugetlb
  [    0.230503] Initializing cgroup subsys pids
  [    0.231432] CPU: CPU feature xsave disabled, no CPUID level 0xd
  [    0.233625] mce: CPU supports 10 MCE banks
  [    0.234535] Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
  [    0.235488] Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
  [    0.250916] Freeing SMP alternatives memory: 28K (ffffffff820b2000 - ffffffff820b9000)
  [    0.258620] ftrace: allocating 31878 entries in 125 pages
  [    0.292291] smpboot: Max logical packages: 1
  [    0.292979] smpboot: APIC(0) Converting physical 0 to logical package 0
  [    0.294062] x2apic enabled
  [    0.294775] Switched APIC routing to physical x2apic.
  [    0.296242] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
  [    0.297081] smpboot: CPU0: Intel Core i7 9xx (Nehalem Class Core i7) (family: 0x6, model: 0x1a, stepping: 0x3)
  [    0.298727] Performance Events: unsupported p6 CPU model 26 no PMU driver, software events only.
  [    0.300782] x86: Booted up 1 node, 1 CPUs
  [    0.301405] smpboot: Total of 1 processors activated (5199.99 BogoMIPS)
  [    0.303089] devtmpfs: initialized
  [    0.306053] evm: security.selinux
  [    0.306590] evm: security.SMACK64
  [    0.308354] evm: security.SMACK64EXEC
  [    0.308915] evm: security.SMACK64TRANSMUTE
  [    0.309542] evm: security.SMACK64MMAP
  [    0.310113] evm: security.ima
  [    0.310586] evm: security.capability
  [    0.311236] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
  [    0.312590] pinctrl core: initialized pinctrl subsystem
  [    0.313427] RTC time:  5:35:03, date: 05/04/16
  [    0.315133] NET: Registered protocol family 16
  [    0.315908] cpuidle: using governor ladder
  [    0.316534] cpuidle: using governor menu
  [    0.317108] PCCT header not found.
  [    0.317686] ACPI: bus type PCI registered
  [    0.318298] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
  [    0.319192] PCI: Using configuration type 1 for base access
  [    0.320935] ACPI: Added _OSI(Module Device)
  [    0.321524] ACPI: Added _OSI(Processor Device)
  [    0.322129] ACPI: Added _OSI(3.0 _SCP Extensions)
  [    0.322761] ACPI: Added _OSI(Processor Aggregator Device)
  [    0.324221] ACPI: Interpreter enabled
  [    0.324764] ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [\_S1_] (20150930/hwxface-580)
  [    0.326118] ACPI Exception: AE_NOT_FOUND, While evaluating Sleep State [\_S2_] (20150930/hwxface-580)
  [    0.327447] ACPI: (supports S0 S3 S4 S5)
  [    0.328000] ACPI: Using IOAPIC for interrupt routing
  [    0.328670] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug
  [    0.331711] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
  [    0.332501] acpi PNP0A03:00: _OSC: OS supports [ASPM ClockPM Segments MSI]
  [    0.333346] acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM
  [    0.334219] acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended PCI configuration space under this bridge.
  [    0.335856] acpiphp: Slot [3] registered
  [    0.336431] acpiphp: Slot [4] registered
  [    0.336997] acpiphp: Slot [5] registered
  [    0.337563] acpiphp: Slot [6] registered
  [    0.339449] acpiphp: Slot [7] registered
  [    0.348585] acpiphp: Slot [8] registered
  [    0.349160] acpiphp: Slot [9] registered
  [    0.349731] acpiphp: Slot [10] registered
  [    0.350315] acpiphp: Slot [11] registered
  [    0.350891] acpiphp: Slot [12] registered
  [    0.351465] acpiphp: Slot [13] registered
  [    0.352053] acpiphp: Slot [14] registered
  [    0.352637] acpiphp: Slot [15] registered
  [    0.353224] acpiphp: Slot [16] registered
  [    0.353799] acpiphp: Slot [17] registered
  [    0.354382] acpiphp: Slot [18] registered
  [    0.354956] acpiphp: Slot [19] registered
  [    0.355533] acpiphp: Slot [20] registered
  [    0.356105] acpiphp: Slot [21] registered
  [    0.356686] acpiphp: Slot [22] registered
  [    0.357261] acpiphp: Slot [23] registered
  [    0.357834] acpiphp: Slot [24] registered
  [    0.358500] acpiphp: Slot [25] registered
  [    0.359114] acpiphp: Slot [26] registered
  [    0.359721] acpiphp: Slot [27] registered
  [    0.360294] acpiphp: Slot [28] registered
  [    0.360884] acpiphp: Slot [29] registered
  [    0.361463] acpiphp: Slot [30] registered
  [    0.362061] acpiphp: Slot [31] registered
  [    0.362640] PCI host bridge to bus 0000:00
  [    0.363218] pci_bus 0000:00: root bus resource [io  0x0000-0x0cf7 window]
  [    0.364054] pci_bus 0000:00: root bus resource [io  0x0d00-0xffff window]
  [    0.364895] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff window]
  [    0.365913] pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window]
  [    0.366933] pci_bus 0000:00: root bus resource [bus 00-ff]
  [    0.377218] pci 0000:00:01.1: legacy IDE quirk: reg 0x10: [io  0x01f0-0x01f7]
  [    0.378115] pci 0000:00:01.1: legacy IDE quirk: reg 0x14: [io  0x03f6]
  [    0.379563] pci 0000:00:01.1: legacy IDE quirk: reg 0x18: [io  0x0170-0x0177]
  [    0.380477] pci 0000:00:01.1: legacy IDE quirk: reg 0x1c: [io  0x0376]
  [    0.387873] pci 0000:00:01.3: quirk: [io  0x0600-0x063f] claimed by PIIX4 ACPI
  [    0.388875] pci 0000:00:01.3: quirk: [io  0x0700-0x070f] claimed by PIIX4 SMB
  [    0.465906] ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11)
  [    0.467014] ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11)
  [    0.468064] ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11)
  [    0.469125] ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11)
  [    0.471532] ACPI: PCI Interrupt Link [LNKS] (IRQs *9)
  [    0.472585] ACPI: Enabled 16 GPEs in block 00 to 0F
  [    0.473485] vgaarb: setting as boot device: PCI:0000:00:02.0
  [    0.474215] vgaarb: device added: PCI:0000:00:02.0,decodes=io+mem,owns=io+mem,locks=none
  [    0.475270] vgaarb: loaded
  [    0.475696] vgaarb: bridge control possible 0000:00:02.0
  [    0.476672] SCSI subsystem initialized
  [    0.477271] ACPI: bus type USB registered
  [    0.477860] usbcore: registered new interface driver usbfs
  [    0.478614] usbcore: registered new interface driver hub
  [    0.479309] usbcore: registered new device driver usb
  [    0.480158] PCI: Using ACPI for IRQ routing
  [    0.480957] NetLabel: Initializing
  [    0.481458] NetLabel:  domain hash size = 128
  [    0.482057] NetLabel:  protocols = UNLABELED CIPSOv4
  [    0.482716] NetLabel:  unlabeled traffic allowed by default
  [    0.483498] clocksource: Switched to clocksource kvm-clock
  [    0.490934] AppArmor: AppArmor Filesystem Enabled
  [    0.491635] pnp: PnP ACPI init
  [    0.492436] pnp: PnP ACPI: found 6 devices
  [    0.500252] clocksource: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: 2085701024 ns
  [    0.501486] NET: Registered protocol family 2
  [    0.502247] TCP established hash table entries: 32768 (order: 6, 262144 bytes)
  [    0.503283] TCP bind hash table entries: 32768 (order: 7, 524288 bytes)
  [    0.504146] TCP: Hash tables configured (established 32768 bind 32768)
  [    0.504963] UDP hash table entries: 2048 (order: 4, 65536 bytes)
  [    0.505719] UDP-Lite hash table entries: 2048 (order: 4, 65536 bytes)
  [    0.506557] NET: Registered protocol family 1
  [    0.507157] pci 0000:00:00.0: Limiting direct PCI/PCI transfers
  [    0.507914] pci 0000:00:01.0: PIIX3: Enabling Passive Release
  [    0.508646] pci 0000:00:01.0: Activating ISA DMA hang workarounds
  [    0.510002] Trying to unpack rootfs image as initramfs...
  [    1.717098] Freeing initrd memory: 7252K (ffff8800371c6000 - ffff8800378db000)
  [    1.718412] PCI-DMA: Using software bounce buffering for IO (SWIOTLB)
  [    1.719192] software IO TLB [mem 0xbbfe0000-0xbffe0000] (64MB) mapped at [ffff8800bbfe0000-ffff8800bffdffff]
  [    1.725831] Scanning for low memory corruption every 60 seconds
  [    1.731157] futex hash table entries: 256 (order: 2, 16384 bytes)
  [    1.731891] audit: initializing netlink subsys (disabled)
  [    1.732583] audit: type=2000 audit(1462340105.446:1): initialized
  [    1.733541] Initialise system trusted keyring
  [    1.734188] HugeTLB registered 1 GB page size, pre-allocated 0 pages
  [    1.734913] HugeTLB registered 2 MB page size, pre-allocated 0 pages
  [    1.736700] zbud: loaded
  [    1.737254] VFS: Disk quotas dquot_6.6.0
  [    1.737797] VFS: Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
  [    1.738984] fuse init (API version 7.23)
  [    1.739650] Key type big_key registered
  [    1.740289] Key type asymmetric registered
  [    1.740823] Asymmetric key parser 'x509' registered
  [    1.741422] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 249)
  [    1.742418] io scheduler noop registered
  [    1.742951] io scheduler deadline registered (default)
  [    1.743580] io scheduler cfq registered
  [    1.744138] pci_hotplug: PCI Hot Plug PCI Core version: 0.5
  [    1.744813] pciehp: PCI Express Hot Plug Controller Driver version: 0.4
  [    1.745653] input: Power Button as /devices/LNXSYSTM:00/LNXPWRBN:00/input/input0
  [    1.746619] ACPI: Power Button [PWRF]
  [    1.747193] GHES: HEST is not enabled!
  [    1.763884] ACPI: PCI Interrupt Link [LNKC] enabled at IRQ 11
  [    1.764640] virtio-pci 0000:00:03.0: virtio_pci: leaving for legacy driver
  [    1.782055] ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 10
  [    1.782747] virtio-pci 0000:00:04.0: virtio_pci: leaving for legacy driver
  [    1.799998] ACPI: PCI Interrupt Link [LNKA] enabled at IRQ 10
  [    1.800665] virtio-pci 0000:00:05.0: virtio_pci: leaving for legacy driver
  [    1.817293] ACPI: PCI Interrupt Link [LNKB] enabled at IRQ 11
  [    1.817943] virtio-pci 0000:00:06.0: virtio_pci: leaving for legacy driver
  [    1.819651] Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled
  [    1.842639] 00:04: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
  [    1.866310] 00:05: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
  [    1.887604] Linux agpgart interface v0.103
  [    1.889620] brd: module loaded
  [    1.890749] loop: module loaded
  [    1.908069]  vda: vda1
  [    1.909586] scsi host0: ata_piix
  [    1.910066] scsi host1: ata_piix
  [    1.910562] ata1: PATA max MWDMA2 cmd 0x1f0 ctl 0x3f6 bmdma 0xc0e0 irq 14
  [    1.911256] ata2: PATA max MWDMA2 cmd 0x170 ctl 0x376 bmdma 0xc0e8 irq 15
  [    1.912214] libphy: Fixed MDIO Bus: probed
  [    1.912753] tun: Universal TUN/TAP device driver, 1.6
  [    1.913312] tun: (C) 1999-2004 Max Krasnyansky <maxk@xxxxxxxxxxxx>
  [    1.930649] PPP generic driver version 2.4.2
  [    1.931288] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
  [    1.932010] ehci-pci: EHCI PCI platform driver
  [    1.932597] ehci-platform: EHCI generic platform driver
  [    1.933234] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
  [    1.933950] ohci-pci: OHCI PCI platform driver
  [    1.934539] ohci-platform: OHCI generic platform driver
  [    1.935191] uhci_hcd: USB Universal Host Controller Interface driver
  [    1.952374] uhci_hcd 0000:00:01.2: UHCI Host Controller
  [    1.953034] uhci_hcd 0000:00:01.2: new USB bus registered, assigned bus number 1
  [    1.953952] uhci_hcd 0000:00:01.2: detected 2 ports
  [    1.954651] uhci_hcd 0000:00:01.2: irq 10, io base 0x0000c040
  [    1.955379] usb usb1: New USB device found, idVendor=1d6b, idProduct=0001
  [    1.956168] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
  [    1.957139] usb usb1: Product: UHCI Host Controller
  [    1.957768] usb usb1: Manufacturer: Linux 4.4.0-21-generic uhci_hcd
  [    1.958543] usb usb1: SerialNumber: 0000:00:01.2
  [    1.959264] hub 1-0:1.0: USB hub found
  [    1.959936] hub 1-0:1.0: 2 ports detected
  [    1.960616] i8042: PNP: PS/2 Controller [PNP0303:KBD,PNP0f13:MOU] at 0x60,0x64 irq 1,12
  [    1.962228] serio: i8042 KBD port at 0x60,0x64 irq 1
  [    1.962900] serio: i8042 AUX port at 0x60,0x64 irq 12
  [    1.963656] mousedev: PS/2 mouse device common for all mice
  [    1.964524] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input1
  [    1.965802] rtc_cmos 00:00: RTC can wake from S4
  [    1.966583] rtc_cmos 00:00: rtc core: registered rtc_cmos as rtc0
  [    1.967397] rtc_cmos 00:00: alarms up to one day, 114 bytes nvram
  [    1.968119] i2c /dev entries driver
  [    1.968702] device-mapper: uevent: version 1.0.3
  [    1.969336] device-mapper: ioctl: 4.34.0-ioctl (2015-10-28) initialised: dm-devel@xxxxxxxxxx
  [    1.970428] ledtrig-cpu: registered to indicate activity on CPUs
  [    1.971346] NET: Registered protocol family 10
  [    1.972135] NET: Registered protocol family 17
  [    1.972732] Key type dns_resolver registered
  [    1.973409] microcode: CPU0 sig=0x106a3, pf=0x1, revision=0x1
  [    1.974182] microcode: Microcode Update Driver: v2.01 <tigran@xxxxxxxxxxxxxxxxxxxx>, Peter Oruba
  [    1.975389] registered taskstats version 1
  [    1.975957] Loading compiled-in X.509 certificates
  [    1.977206] Loaded X.509 cert 'Build time autogenerated kernel key: fc7c0e9f152f32eca50ea2d9722926e5127af244'
  [    1.978456] zswap: loaded using pool lzo/zbud
  [    1.980197] Key type trusted registered
  [    1.992720] Key type encrypted registered
  [    1.993250] AppArmor: AppArmor sha1 policy hashing enabled
  [    1.993898] ima: No TPM chip found, activating TPM-bypass!
  [    1.994625] evm: HMAC attrs: 0x1
  [    1.995271]   Magic number: 0:849:566
  [    1.995909] rtc_cmos 00:00: setting system clock to 2016-05-04 05:35:05 UTC (1462340105)
  [    1.997035] BIOS EDD facility v0.16 2004-Jun-25, 0 devices found
  [    1.997702] EDD information not available.
  [    2.073644] Freeing unused kernel memory: 1476K (ffffffff81f41000 - ffffffff820b2000)
  [    2.075469] Write protecting the kernel read-only data: 14336k
  [    2.077486] Freeing unused kernel memory: 1872K (ffff88000182c000 - ffff880001a00000)
  [    2.079999] Freeing unused kernel memory: 176K (ffff880001dd4000 - ffff880001e00000)
  Loading, please wait...
  starting version 229
  [    2.095265] random: udevadm urandom read with 2 bits of entropy available
  [    2.140733] virtio_net virtio0 ens3: renamed from eth0
  [    2.148962] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input4
  [    2.150419] input: VirtualPS/2 VMware VMMouse as /devices/platform/i8042/serio1/input/input3
  [    2.179873] FDC 0 is a S82078B
  [    2.723675] tsc: Refined TSC clocksource calibration: 2600.056 MHz
  [    2.725415] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x257a71592ee, max_idle_ns: 440795334892 ns
  Begin: Loading essential drivers ... [    3.549857] md: linear personality registered for level -1
  [    3.554621] md: multipath personality registered for level -4
  [    3.559487] md: raid0 personality registered for level 0
  [    3.564545] md: raid1 personality registered for level 1
  [    3.639509] raid6: sse2x1   gen()  6920 MB/s
  [    3.707518] raid6: sse2x1   xor()  5781 MB/s
  [    3.775508] raid6: sse2x2   gen()  9630 MB/s
  [    3.843506] raid6: sse2x2   xor()  5438 MB/s
  [    3.911506] raid6: sse2x4   gen() 11722 MB/s
  [    3.979503] raid6: sse2x4   xor()  7960 MB/s
  [    3.983515] invalid opcode: 0000 [#1] SMP 
  [    3.984205] Modules linked in: raid6_pq(+) libcrc32c raid1 raid0 multipath linear psmouse floppy
  [    3.985859] CPU: 0 PID: 230 Comm: modprobe Not tainted 4.4.0-21-generic #37-Ubuntu
  [    3.986881] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Ubuntu-1.8.2-1ubuntu1~cloud0 04/01/2014
  [    3.988118] task: ffff8800bb1d7080 ti: ffff8800b9a48000 task.ti: ffff8800b9a48000
  [    3.989124] RIP: 0010:[<ffffffffc0061a8d>]  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
  [    3.992121] RSP: 0018:ffff8800b9a4bb78  EFLAGS: 00010246
  [    3.992808] RAX: 0000000000000000 RBX: ffff8800b9a4bbc8 RCX: 00000000fffedeae
  [    3.993669] RDX: 0000000000000080 RSI: 0000000000001000 RDI: 0000000000000012
  [    3.994541] RBP: ffff8800b9a4bba8 R08: 0000000000000000 R09: 00000000000001bd
  [    3.995446] R10: 00000000fffede9d R11: 00000000000001bd R12: 0000000000001000
  [    3.996307] R13: ffff8800bb022000 R14: ffff8800bb023000 R15: 0000000000000012
  [    3.997167] FS:  00007fa2699f6700(0000) GS:ffff88013fc00000(0000) knlGS:0000000000000000
  [    3.998245] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [    3.998974] CR2: 000056292fa0b008 CR3: 00000000b9a19000 CR4: 00000000001006f0
  [    3.999840] Stack:
  [    4.000204]  0000000000000080 ffffffffc00747a0 0000000000000001 0000000000003fb0
  [    4.001439]  ffffffffc0062238 ffff8800bb022000 ffff8800b9a4bc88 ffffffffc0079116
  [    4.002684]  00000000fffedeae 0000000000002ee4 ffffffffc0064600 ffffffffc0065600
  [    4.004020] Call Trace:
  [    4.004429]  [<ffffffffc0079116>] init_module+0x116/0x1000 [raid6_pq]
  [    4.005243]  [<ffffffffc0079000>] ? 0xffffffffc0079000
  [    4.005917]  [<ffffffff81002123>] do_one_initcall+0xb3/0x200
  [    4.006651]  [<ffffffff818205f8>] ? preempt_schedule_common+0x18/0x30
  [    4.007451]  [<ffffffff8182062c>] ? _cond_resched+0x1c/0x30
  [    4.008214]  [<ffffffff811eaeb3>] ? kmem_cache_alloc_trace+0x183/0x1f0
  [    4.009021]  [<ffffffff8118c163>] do_init_module+0x5f/0x1cf
  [    4.009734]  [<ffffffff81109df7>] load_module+0x1667/0x1c00
  [    4.010458]  [<ffffffff811063a0>] ? __symbol_put+0x60/0x60
  [    4.011163]  [<ffffffff812126b0>] ? kernel_read+0x50/0x80
  [    4.011861]  [<ffffffff8110a5d4>] SYSC_finit_module+0xb4/0xe0
  [    4.012590]  [<ffffffff8110a61e>] SyS_finit_module+0xe/0x10
  [    4.013302]  [<ffffffff818244f2>] entry_SYSCALL_64_fastpath+0x16/0x71
  [    4.014104] Code: 55 41 54 53 48 89 d3 48 8d 14 c5 00 00 00 00 41 89 ff 49 89 f4 48 83 ec 08 4c 8b 2c c3 4c 8b 74 13 08 48 89 55 d0 e8 53 83 fd c0 <c5> fd 6f 05 8b 2e 01 00 c5 e5 ef db 4d 85 e4 48 8b 55 d0 0f 84 
  [    4.020068] RIP  [<ffffffffc0061a8d>] raid6_avx21_gen_syndrome+0x3d/0x120 [raid6_pq]
  [    4.023317]  RSP <ffff8800b9a4bb78>
  [    4.023847] ---[ end trace b3853dc6e5fc1f8f ]---
  Segmentation fault

  And here's the corresponding Libvirt XML:

  <domain type='kvm' id='411'>
    <name>instance-000030cd</name>
    <uuid>587a3497-3198-4c19-87c4-ddf449385f71</uuid>
    <metadata>
      <nova:instance xmlns:nova="http://openstack.org/xmlns/libvirt/nova/1.0";>
        <nova:package version="12.0.1"/>
        <nova:name>test-xenial-segfault</nova:name>
        <nova:creationTime>2016-05-04 05:39:55</nova:creationTime>
        <nova:flavor name="m1.small">
          <nova:memory>4096</nova:memory>
          <nova:disk>16</nova:disk>
          <nova:swap>0</nova:swap>
          <nova:ephemeral>0</nova:ephemeral>
          <nova:vcpus>1</nova:vcpus>
        </nova:flavor>
        <nova:owner>
          <nova:user uuid="07d961b93aed45c0b7989f91c40341ae">username</nova:user>
          <nova:project uuid="dd4f48116bd942f9b145d20e9f1a11be">project</nova:project>
        </nova:owner>
        <nova:root type="image" uuid="4b5b61a5-008c-4424-a899-f6896384a55c"/>
      </nova:instance>
    </metadata>
    <memory unit='KiB'>4194304</memory>
    <currentMemory unit='KiB'>4194304</currentMemory>
    <vcpu placement='static'>1</vcpu>
    <cputune>
      <shares>1024</shares>
    </cputune>
    <resource>
      <partition>/machine</partition>
    </resource>
    <sysinfo type='smbios'>
      <system>
        <entry name='manufacturer'>OpenStack Foundation</entry>
        <entry name='product'>OpenStack Nova</entry>
        <entry name='version'>12.0.1</entry>
        <entry name='serial'>00000000-0000-0000-0000-0cc47a349290</entry>
        <entry name='uuid'>587a3497-3198-4c19-87c4-ddf449385f71</entry>
        <entry name='family'>Virtual Machine</entry>
      </system>
    </sysinfo>
    <os>
      <type arch='x86_64' machine='pc-i440fx-vivid'>hvm</type>
      <boot dev='hd'/>
      <smbios mode='sysinfo'/>
    </os>
    <features>
      <acpi/>
      <apic/>
    </features>
    <cpu mode='host-model'>
      <model fallback='allow'/>
      <topology sockets='1' cores='1' threads='1'/>
    </cpu>
    <clock offset='utc'>
      <timer name='pit' tickpolicy='delay'/>
      <timer name='rtc' tickpolicy='catchup'/>
      <timer name='hpet' present='no'/>
    </clock>
    <on_poweroff>destroy</on_poweroff>
    <on_reboot>restart</on_reboot>
    <on_crash>destroy</on_crash>
    <devices>
      <emulator>/usr/bin/qemu-system-x86_64</emulator>
      <disk type='network' device='disk'>
        <driver name='qemu' type='raw' cache='writeback'/>
        <auth username='cinder'>
          <secret type='ceph' uuid='23c33478-af4c-49d0-bb46-9890d6b89084'/>
        </auth>
        <source protocol='rbd' name='libvirt/587a3497-3198-4c19-87c4-ddf449385f71_disk'>
          <host name='172.24.3.17' port='6789'/>
          <host name='172.24.3.18' port='6789'/>
          <host name='172.24.3.19' port='6789'/>
          <host name='172.24.3.25' port='6789'/>
          <host name='172.24.3.26' port='6789'/>
        </source>
        <backingStore/>
        <target dev='vda' bus='virtio'/>
        <alias name='virtio-disk0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
      </disk>
      <controller type='usb' index='0'>
        <alias name='usb'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
      </controller>
      <controller type='pci' index='0' model='pci-root'>
        <alias name='pci.0'/>
      </controller>
      <controller type='virtio-serial' index='0'>
        <alias name='virtio-serial0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
      </controller>
      <interface type='bridge'>
        <mac address='fa:16:3e:3c:5e:88'/>
        <source bridge='qbrba81b423-ab'/>
        <target dev='tapba81b423-ab'/>
        <model type='virtio'/>
        <alias name='net0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
      </interface>
      <serial type='file'>
        <source path='/var/lib/nova/instances/587a3497-3198-4c19-87c4-ddf449385f71/console.log'/>
        <target port='0'/>
        <alias name='serial0'/>
      </serial>
      <serial type='pty'>
        <source path='/dev/pts/34'/>
        <target port='1'/>
        <alias name='serial1'/>
      </serial>
      <console type='file'>
        <source path='/var/lib/nova/instances/587a3497-3198-4c19-87c4-ddf449385f71/console.log'/>
        <target type='serial' port='0'/>
        <alias name='serial0'/>
      </console>
      <channel type='pty'>
        <source path='/dev/pts/35'/>
        <target type='virtio' name='com.redhat.spice.0' state='disconnected'/>
        <alias name='channel0'/>
        <address type='virtio-serial' controller='0' bus='0' port='1'/>
      </channel>
      <input type='mouse' bus='ps2'/>
      <input type='keyboard' bus='ps2'/>
      <graphics type='spice' port='5915' autoport='yes' listen='172.24.1.35' keymap='fr-ch'>
        <listen type='address' address='172.24.1.35'/>
      </graphics>
      <video>
        <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1'/>
        <alias name='video0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
      </video>
      <memballoon model='virtio'>
        <stats period='10'/>
        <alias name='balloon0'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
      </memballoon>
    </devices>
    <seclabel type='dynamic' model='apparmor' relabel='yes'>
      <label>libvirt-587a3497-3198-4c19-87c4-ddf449385f71</label>
      <imagelabel>libvirt-587a3497-3198-4c19-87c4-ddf449385f71</imagelabel>
    </seclabel>
  </domain>

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