[ BUG] Freebsd 10.3 32 failes to boot with double fault reporting in console.

[Zhanghailiang]

Hi,
         We hit a bug while tried to boot Freebsd 10.3 32 as a VM in KVM host.
We can reproduce it stably with Intel Skylake V5 CPU. We have tried the new upstream linux as Host,
It still appears. Does any one come across such problems ?


Thanks.

The Host Hardware info is：
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                80
On-line CPU(s) list:   0-79
Thread(s) per core:    2
Core(s) per socket:    20
Socket(s):             2
NUMA node(s):          2
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 85
Model name:            Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz
Stepping:              4
CPU MHz:               3099.999
BogoMIPS:              4800.00
Virtualization:        VT-x
L1d cache:             32K
L1i cache:             32K
L2 cache:              1024K
L3 cache:              28160K
NUMA node0 CPU(s):     0-19,40-59
NUMA node1 CPU(s):     20-39,60-79
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 intel_ppin intel_pt mba tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm mpx rdt_a avx512f avx512dq rdseed adx smap clflushopt clwb avx512cd avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts pku ospke

The bellow messages is gotten from Freebsd VM.
/boot/kernel/kernel text=0xf945d5 data=0xdc110+0x161488 syms=[0x4+0xd9020+0x4+0x1601ff]
Booting...
Copyright (c) 1992-2016 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
         The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 10.3-RELEASE #0 r297264: Fri Mar 25 03:51:29 UTC 2016
    root at releng1.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC i386
FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512
CPU: Intel(R) Xeon(R) Gold 6148 CPU @ 2.40GHz (2400.05-MHz 686-class CPU)
  Origin="GenuineIntel"  Id=0x50654  Family=0x6  Model=0x55  Stepping=4
  Features=0xf83fbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE,SSE2,SS>
  Features2=0xfffa3203<SSE3,PCLMULQDQ,SSSE3,FMA,CX16,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,TSCDLT,AESNI,XSAVE,OSXSAVE,AVX,F16C,RDRAND,HV>
  AMD Features=0x2c100800<SYSCALL,NX,Page1GB,RDTSCP,LM>
  AMD Features2=0x121<LAHF,ABM,Prefetch>
  Structured Extended Features=0xd19f4f3a<TSCADJ,BMI1,HLE,AVX2,BMI2,ERMS,INVPCID,RTM,MPX,AVX512F,RDSEED,ADX,SMAP,CLFLUSHOPT,AVX512CD>
  Structured Extended Features2=0x8<PKU>
  XSAVE Features=0xf<XSAVEOPT,XSAVEC,XINUSE,XSAVES>
Hypervisor: Origin = "KVMKVMKVM"
real memory  = 17179869184 (16384 MB)
avail memory = 3137024000 (2991 MB)
Event timer "LAPIC" quality 600
ACPI APIC Table: <BOCHS  BXPCAPIC>
FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs
FreeBSD/SMP: 8 package(s) x 1 core(s)
cpu0 (BSP): APIC ID:  0
cpu1 (AP): APIC ID:  1
cpu2 (AP): APIC ID:  2
cpu3 (AP): APIC ID:  3
cpu4 (AP): APIC ID:  4
cpu5 (AP): APIC ID:  5
cpu6 (AP): APIC ID:  6
cpu7 (AP): APIC ID:  7
random: <Software, Yarrow> initialized
ioapic0 <Version 1.1> irqs 0-23 on motherboard
kbd1 at kbdmux0
acpi0: <BOCHS BXPCRSDT> on motherboard
acpi0: Power Button (fixed)
cpu0: <ACPI CPU> on acpi0
cpu1: <ACPI CPU> on acpi0
cpu2: <ACPI CPU> on acpi0
cpu3: <ACPI CPU> on acpi0
cpu4: <ACPI CPU> on acpi0
cpu5: <ACPI CPU> on acpi0
cpu6: <ACPI CPU> on acpi0
cpu7: <ACPI CPU> on acpi0
atrtc0: <AT realtime clock> port 0x70-0x71,0x72-0x77 irq 8 on acpi0
Event timer "RTC" frequency 32768 Hz quality 0
Timecounter "ACPI-fast" frequency 3579545 Hz quality 900
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x608-0x60b on acpi0
pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
pci0: <ACPI PCI bus> on pcib0
isab0: <PCI-ISA bridge> at device 1.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel PIIX3 WDMA2 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xc0e0-0xc0ef at device 1.1 on pci0
ata0: <ATA channel> at channel 0 on atapci0
ata1: <ATA channel> at channel 1 on atapci0
uhci0: <Intel 82371SB (PIIX3) USB controller> port 0xc080-0xc09f irq 11 at device 1.2 on pci0
usbus0 on uhci0
pci0: <bridge> at device 1.3 (no driver attached)
vgapci0: <VGA-compatible display> mem 0xfc000000-0xfdffffff,0xfebd0000-0xfebd0fff at device 2.0 on pci0
vgapci0: Boot video device
virtio_pci0: <VirtIO PCI Network adapter> port 0xc0a0-0xc0bf mem 0xfebd1000-0xfebd1fff,0xfe000000-0xfe003fff irq 11 at device 3.0 on pci0
vtnet0: <VirtIO Networking Adapter> on virtio_pci0
vtnet0: Ethernet address: 52:54:00:7c:fa:82
virtio_pci1: <VirtIO PCI SCSI adapter> port 0xc000-0xc03f mem 0xfebd2000-0xfebd2fff,0xfe004000-0xfe007fff irq 10 at device 5.0 on pci0
vtscsi0: <VirtIO SCSI Adapter> on virtio_pci1
virtio_pci2: <VirtIO PCI Console adapter> port 0xc040-0xc07f mem 0xfebd3000-0xfebd3fff,0xfe008000-0xfe00bfff irq 10 at device 6.0 on pci0
virtio_pci3: <VirtIO PCI Balloon adapter> port 0xc0c0-0xc0df mem 0xfe00c000-0xfe00ffff irq 10 at device 9.0 on pci0
vtballoon0: <VirtIO Balloon Adapter> on virtio_pci3
atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
atkbd0: [GIANT-LOCKED]
psm0: <PS/2 Mouse> irq 12 on atkbdc0
psm0: [GIANT-LOCKED]
psm0: model IntelliMouse Explorer, device ID 4
fdc0: <floppy drive controller (FDE)> port 0x3f2-0x3f5,0x3f7 irq 6 drq 2 on acpi0
fdc0: does not respond
device_attach: fdc0 attach returned 6
uart0: <16550 or compatible> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
uart0: console (9600,n,8,1)
pmtimer0 on isa0
orm0: <ISA Option ROM> at iomem 0xeb000-0xeffff pnpid ORM0000 on isa0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x100>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
attimer0: <AT timer> at port 0x40 on isa0
Timecounter "i8254" frequency 1193182 Hz quality 0
Event timer "i8254" frequency 1193182 Hz quality 100
fdc0: No FDOUT register!
ppc0: parallel port not found.
Timecounters tick every 1.000 msec
usbus0: 12Mbps Full Speed USB v1.0
ugen0.1: <Intel> at usbus0
uhub0: <Intel UHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus0
random: unblocking device.
ada0 at ata0 bus 0 scbus0 target 0 lun 0
ada0: <QEMU HARDDISK 2.5+> ATA-7 device
ada0: Serial Number QM00001
ada0: 16.700MB/s transfers
Fatal double fault:
eip = 0xc0b1fac3
esp = 0xe3b24000
ebp = 0xe3b24000
cpuid = 0; apic id = 00
panic: double fault
cpuid = 0
KDB: stack backtrace:
#0 0xc0b7be92 at kdb_backtrace+0x52
#1 0xc0b3c1db at vpanic+0x11b
#2 0xc0b3c0bb at panic+0x1b
#3 0xc10655fb at dblfault_handler+0xab
Uptime: 1s
Automatic reboot in 15 seconds - press a key on the console to abort