Re: KVM Disk i/o or VM activities causes soft lockup?

[Stefan Hajnoczi]

On Fri, Nov 23, 2012 at 10:34:16AM -0800, Vincent Li wrote:
> On Thu, Nov 22, 2012 at 11:29 PM, Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote:
> > On Wed, Nov 21, 2012 at 03:36:50PM -0800, Vincent Li wrote:
> >> We have users running on redhat based distro (Kernel
> >> 2.6.32-131.21.1.el6.x86_64 ) with kvm, when customer made cron job
> >> script to copy large files between kvm guest or some other user space
> >> program leads to disk i/o or VM activities, users get following soft
> >> lockup message from console:
> >>
> >> Nov 17 13:44:46 slot1/luipaard100a err kernel: BUG: soft lockup -
> >> CPU#4 stuck for 61s! [qemu-kvm:6795]
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel: Modules linked in:
> >> ebt_vlan nls_utf8 isofs ebtable_filter ebtables 8021q garp bridge stp
> >> llc ipt_REJECT iptable_filter xt_NOTRACK nf_conntrack iptable_raw
> >> ip_tables loop ext2 binfmt_misc hed womdict(U) vnic(U) parport_pc lp
> >> parport predis(U) lasthop(U) ipv6 toggler vhost_net tun kvm_intel kvm
> >> jiffies(U) sysstats hrsleep i2c_dev datastor(U) linux_user_bde(P)(U)
> >> linux_kernel_bde(P)(U) tg3 libphy serio_raw i2c_i801 i2c_core ehci_hcd
> >> raid1 raid0 virtio_pci virtio_blk virtio virtio_ring mvsas libsas
> >> scsi_transport_sas mptspi mptscsih mptbase scsi_transport_spi 3w_9xxx
> >> sata_svw(U) ahci serverworks sata_sil ata_piix libata sd_mod
> >> crc_t10dif amd74xx piix ide_gd_mod ide_core dm_snapshot dm_mirror
> >> dm_region_hash dm_log dm_mod ext3 jbd mbcache
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel: Pid: 6795, comm:
> >> qemu-kvm Tainted: P           ----------------
> >> 2.6.32-131.21.1.el6.f5.x86_64 #1
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel: Call Trace:
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel: <IRQ>
> >> [<ffffffff81084f95>] ? get_timestamp+0x9/0xf
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff810855d6>] ? watchdog_timer_fn+0x130/0x178
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff81059f11>] ? __run_hrtimer+0xa3/0xff
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff8105a188>] ? hrtimer_interrupt+0xe6/0x190
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff8105a14b>] ? hrtimer_interrupt+0xa9/0x190
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff8101e5a9>] ? hpet_interrupt_handler+0x26/0x2d
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff8105a26f>] ? hrtimer_peek_ahead_timers+0x9/0xd
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff81044fcc>] ? __do_softirq+0xc5/0x17a
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff81003adc>] ? call_softirq+0x1c/0x28
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff8100506b>] ? do_softirq+0x31/0x66
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff81003673>] ? call_function_interrupt+0x13/0x20
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel: <EOI>
> >> [<ffffffffa0219986>] ? vmx_get_msr+0x0/0x123 [kvm_intel]
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffffa01d11c0>] ? kvm_arch_vcpu_ioctl_run+0x80e/0xaf1 [kvm]
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffffa01d11b4>] ? kvm_arch_vcpu_ioctl_run+0x802/0xaf1 [kvm]
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff8114e59b>] ? inode_has_perm+0x65/0x72
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffffa01c77f5>] ? kvm_vcpu_ioctl+0xf2/0x5ba [kvm]
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff8114e642>] ? file_has_perm+0x9a/0xac
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff810f9ec2>] ? vfs_ioctl+0x21/0x6b
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff810fa406>] ? do_vfs_ioctl+0x487/0x4da
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff810fa4aa>] ? sys_ioctl+0x51/0x70
> >> Nov 17 13:44:46 slot1/luipaard100a warning kernel:
> >> [<ffffffff810029d1>] ? system_call_fastpath+0x3c/0x41
> >
> > This soft lockup is report on the host?
> >
> > Stefan
> 
> Yes, it is on host. we just recommend users not doing large file
> copying, just wondering if there is potential kernel bug. it seems the
> softlockup backtrace pointing to hrtimer and softirq. my naive
> knowledge is that the watchdog thread is on top of hrtimer which is on
> top of softirq.

Since the soft lockup detector is firing on the host, this seems like a
hardware/driver problem.  Have you ever had soft lockups running non-KVM
workloads on this host?

Stefan
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