** Changed in: linux (Ubuntu)
Assignee: Chris J Arges (arges) => (unassigned)
** Description changed:
[Impact]
- When using KVM on an AMD host with a kernel that has CONFIG_DEBUG_RODATA
enabled, a guest with: multiple vCPUs, and exposing features to the guest such
as tsc_adjust can cause a divide error on kvm_unlock_kick when booting the VM.
+ When using KVM on an AMD host with a kernel that has CONFIG_DEBUG_RODATA
enabled, a guest with: multiple vCPUs, and exposing features to the guest such
as tsc_adjust can cause a divide error on kvm_unlock_kick when booting the VM.
+
+ This impacts kernels 3.12+.
[Test Case]
1) Create a VM on an AMD host with appropriate features (Opteron 6xxx for
example)
2) Edit virsh xml to have <cpu mode='host-passthrough'></cpu> and multiple
vCPUs.
3) Boot VM with VGA console using virt-manager (I couldn't reproduce strictly
monitoring via virsh console).
[Fix]
commit c1118b3602c2329671ad5ec8bdf8e374323d6343 upstream
--
Just upgraded OpenStack compute hosts in our public cloud (using qemu-
kvm via libvirt) from Precise to Trusty (14.04.1), now on kernel
3.13.0-36-generic with qemu-kvm 2.0.0+dfsg-2ubuntu1.5.
Following the upgrade, whenever we try to start an smp/multicore Trusty
guest (existing or new), we run into this panic [1] inside the guest
just towards the end of boot. This happens consistently for smp guests
using the Trusty kernel (i.e., it also affects earlier Ubuntus using the
HWE kernel from Trusty but not their native versions). I didn't have any
other distro images to hand with 3.13.x kernels, but none of the others
I tested were affected (in the 3.2 - 3.16 kernel range).
There are scarce similar reports out there, but the one we did find
pointed to a CPU feature as the trigger. We were running these hosts
with libvirt cpu mode set to "host-passthrough" (so qemu starts with
"-cpu host"), on AMD 6200 & 6300 Opteron hardware. Switching the guest
domains to use cpu mode "host-model" instead works around the issue and
is perfectly acceptable for most of our users.
We have various other Intel compute hosts and they don't seem to be
affected.
(1)
[ 11.256924] divide error: 0000 [#1] SMP
[ 11.258133] Modules linked in: kvm_amd kvm crct10dif_pclmul crc32_pclmul
ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper
cryptd serio_raw lp parport psmouse floppy
[ 11.260228] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.13.0-36-generic
#63-Ubuntu
[ 11.260228] Hardware name: OpenStack Foundation OpenStack Nova, BIOS Bochs
01/01/2011
[ 11.260228] task: ffffffff81c15480 ti: ffffffff81c00000 task.ti:
ffffffff81c00000
[ 11.260228] RIP: 0010:[<ffffffff8104ed58>] [<ffffffff8104ed58>]
kvm_unlock_kick+0xa8/0x100
[ 11.260228] RSP: 0018:ffff88023fc03c98 EFLAGS: 00010046
[ 11.260228] RAX: 0000000000000005 RBX: 0000000000000000 RCX: 0000000000000001
[ 11.260228] RDX: ffffffff81eaf408 RSI: 0000000000000000 RDI: 0000000000000000
[ 11.260228] RBP: ffff88023fc03cb8 R08: ffffffff81eaf400 R09: 00000000ffffffff
[ 11.260228] R10: ffff880037612cc0 R11: ffffea0002eb0a00 R12: ffff8800374a33c0
[ 11.260228] R13: 0000000000000020 R14: 0000000000000001 R15: 0000000000000286
[ 11.260228] FS: 00007f1e8b538740(0000) GS:ffff88023fc00000(0000)
knlGS:0000000000000000
[ 11.260228] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 11.260228] CR2: 00007f1e8ae09d50 CR3: 0000000001c0e000 CR4: 00000000000406f0
[ 11.260228] Stack:
[ 11.260228] 0000000000000286 0000000000000001 0000000000000001
00000000000000c3
[ 11.260228] ffff88023fc03cc8 ffffffff81717ed6 ffff88023fc03ce0
ffffffff8172641a
[ 11.260228] ffff8800374a33c0 ffff88023fc03d18 ffffffff810aaeb0
ffff88023295e000
[ 11.260228] Call Trace:
[ 11.260228] <IRQ>
[ 11.260228] [<ffffffff81717ed6>] __ticket_unlock_slowpath+0x24/0x34
[ 11.260228] [<ffffffff8172641a>] _raw_spin_unlock_irqrestore+0x3a/0x40
[ 11.260228] [<ffffffff810aaeb0>] __wake_up_sync_key+0x50/0x60
[ 11.260228] [<ffffffff8160ca5a>] sock_def_readable+0x3a/0x70
[ 11.260228] [<ffffffff816fda0a>] packet_rcv+0x2fa/0x430
[ 11.260228] [<ffffffff816228b0>] __netif_receive_skb_core+0x360/0x840
[ 11.260228] [<ffffffff81622da8>] __netif_receive_skb+0x18/0x60
[ 11.260228] [<ffffffff81622e13>] netif_receive_skb+0x23/0x90
[ 11.260228] [<ffffffff815288d4>] virtnet_poll+0x4d4/0x850
[ 11.260228] [<ffffffff81623192>] net_rx_action+0x152/0x250
[ 11.260228] [<ffffffff8106cbac>] __do_softirq+0xec/0x2c0
[ 11.260228] [<ffffffff8106d0f5>] irq_exit+0x105/0x110
[ 11.260228] [<ffffffff817312d6>] do_IRQ+0x56/0xc0
[ 11.260228] [<ffffffff81726a6d>] common_interrupt+0x6d/0x6d
[ 11.260228] <EOI>
[ 11.260228] [<ffffffff8104f596>] ? native_safe_halt+0x6/0x10
[ 11.260228] [<ffffffff8101c62f>] default_idle+0x1f/0xc0
[ 11.260228] [<ffffffff8101cef6>] arch_cpu_idle+0x26/0x30
[ 11.260228] [<ffffffff810bed95>] cpu_startup_entry+0xc5/0x290
[ 11.260228] [<ffffffff8170ca77>] rest_init+0x77/0x80
[ 11.260228] [<ffffffff81d35f6b>] start_kernel+0x433/0x43e
[ 11.260228] [<ffffffff81d35941>] ? repair_env_string+0x5c/0x5c
[ 11.260228] [<ffffffff81d35120>] ? early_idt_handlers+0x120/0x120
[ 11.260228] [<ffffffff81d355ee>] x86_64_start_reservations+0x2a/0x2c
[ 11.260228] [<ffffffff81d35733>] x86_64_start_kernel+0x143/0x152
[ 11.260228] Code: 66 44 39 e8 75 bd 0f b6 35 f6 06 e6 00 40 84 f6 75 2a 83
05 06 07 e6 00 01 48 c7 c0 6a b0 00 00 31 db 0f b7 0c 01 b8 05 00 00 00 <0f> 01
c1 0f 1f 44 00 00 5b 41 5c 41 5d 41 5e 5d c3 89 f0 31 c9
[ 11.260228] RIP [<ffffffff8104ed58>] kvm_unlock_kick+0xa8/0x100
[ 11.260228] RSP <ffff88023fc03c98>
[ 11.260228] ---[ end trace f1c26ff24745b331 ]---
[ 11.260228] Kernel panic - not syncing: Fatal exception in interrupt
[ 11.260228] Shutting down cpus with NMI
** Changed in: linux (Ubuntu Trusty)
Status: New => In Progress
** Changed in: linux (Ubuntu Utopic)
Status: New => In Progress
** Changed in: linux (Ubuntu Trusty)
Importance: Undecided => Medium
** Changed in: linux (Ubuntu Utopic)
Importance: Undecided => Medium
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https://bugs.launchpad.net/bugs/1379340
Title:
qemu-kvm guest panic for AMD smp trusty guests
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