qemu-system-x86 crashes with Windows guest and lots of I/O pressure

Hardware HP DL380Gen9, 128GB RAM, 2 CPUs

Windows guest causing lots of I/O pressure caused qemu to crash.

$ lsb_release -rd
Description: Ubuntu 14.04.2 LTS
Release: 14.04

ii qemu-system-x86 2.0.0+dfsg-2ubuntu1.10 amd64 QEMU full system emulation binaries (x86)

[151743.650896] INFO: task jbd2/dm-0-8:573 blocked for more than 120 seconds.
[151743.651338] Not tainted 3.16.0-34-generic #47~14.04.1-Ubuntu
[151743.651745] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[151743.652279] jbd2/dm-0-8 D ffff88103fc130c0 0 573 2 0x00000000
[151743.652286] ffff88102618bcb0 0000000000000046 ffff8820244adbb0 ffff88102618bfd8
[151743.652291] 00000000000130c0 00000000000130c0 ffffffff81c1a480 ffff88102618bd98
[151743.652295] ffff8810241150b8 ffff8820244adbb0 ffff88101a66eb00 ffff88102618bd80
[151743.652299] Call Trace:
[151743.652312] [<ffffffff817689d9>] schedule+0x29/0x70
[151743.652323] [<ffffffff8129db99>] jbd2_journal_commit_transaction+0x279/0x19b0
[151743.652332] [<ffffffff810b4d70>] ? prepare_to_wait_event+0x100/0x100
[151743.652341] [<ffffffff8107a69b>] ? lock_timer_base.isra.34+0x2b/0x50
[151743.652346] [<ffffffff812a29fb>] kjournald2+0xbb/0x240
[151743.652350] [<ffffffff810b4d70>] ? prepare_to_wait_event+0x100/0x100
[151743.652354] [<ffffffff812a2940>] ? commit_timeout+0x10/0x10
[151743.652361] [<ffffffff81091332>] kthread+0xd2/0xf0
[151743.652368] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[151743.652374] [<ffffffff8176c9bc>] ret_from_fork+0x7c/0xb0
[151743.652379] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[151743.652402] INFO: task kworker/u49:1:16585 blocked for more than 120 seconds.
[151743.652839] Not tainted 3.16.0-34-generic #47~14.04.1-Ubuntu
[151743.653255] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[151743.653741] kworker/u49:1 D ffff88103fd330c0 0 16585 2 0x00000000
[151743.653754] Workqueue: writeback bdi_writeback_workfn (flush-252:0)
[151743.653757] ffff88001c5c3928 0000000000000046 ffff880b9ed65bb0 ffff88001c5c3fd8
[151743.653761] 00000000000130c0 00000000000130c0 ffff881029347010 ffff881024115000
[151743.653765] ffff881024115070 00000000000041be 0000000000000014 ffff88103f67b150
[151743.653769] Call Trace:
[151743.653773] [<ffffffff817689d9>] schedule+0x29/0x70
[151743.653778] [<ffffffff8129aac9>] wait_transaction_locked+0x79/0xa0
[151743.653783] [<ffffffff810b4d70>] ? prepare_to_wait_event+0x100/0x100
[151743.653787] [<ffffffff8129adf0>] start_this_handle+0x280/0x5a0
[151743.653796] [<ffffffff811b7642>] ? kmem_cache_alloc+0x1b2/0x1e0
[151743.653800] [<ffffffff8129b2b0>] ? jbd2__journal_start+0x90/0x1e0
[151743.653805] [<ffffffff8129b313>] jbd2__journal_start+0xf3/0x1e0
[151743.653811] [<ffffffff81257e9c>] ? ext4_writepages+0x3ac/0xd00
[151743.653815] [<ffffffff81282859>] __ext4_journal_start_sb+0x69/0xe0
[151743.653818] [<ffffffff81257e9c>] ext4_writepages+0x3ac/0xd00
[151743.653825] [<ffffffff8116c59d>] ? generic_writepages+0x4d/0x60
[151743.653830] [<ffffffff8116d6ee>] do_writepages+0x1e/0x40
[151743.653834] [<ffffffff811fc360>] __writeback_single_inode+0x40/0x220
[151743.653838] [<ffffffff811fce57>] writeback_sb_inodes+0x247/0x3e0
[151743.653843] [<ffffffff811fd08f>] __writeback_inodes_wb+0x9f/0xd0
[151743.653847] [<ffffffff811fd303>] wb_writeback+0x243/0x2c0
[151743.653851] [<ffffffff811ffa92>] bdi_writeback_workfn+0x2a2/0x430
[151743.653856] [<ffffffff8108a322>] process_one_work+0x182/0x450
[151743.653859] [<ffffffff8108aa91>] worker_thread+0x121/0x570
[151743.653863] [<ffffffff8108a970>] ? rescuer_thread+0x380/0x380
[151743.653868] [<ffffffff81091332>] kthread+0xd2/0xf0
[151743.653872] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[151743.653877] [<ffffffff8176c9bc>] ret_from_fork+0x7c/0xb0
[151743.653881] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[154982.430116] INFO: task jbd2/dm-0-8:573 blocked for more than 120 seconds.
[154982.430527] Not tainted 3.16.0-34-generic #47~14.04.1-Ubuntu
[154982.430907] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[154982.431388] jbd2/dm-0-8 D ffff88103fc730c0 0 573 2 0x00000000
[154982.431396] ffff88102618bcb0 0000000000000046 ffff8820244adbb0 ffff88102618bfd8
[154982.431400] 00000000000130c0 00000000000130c0 ffff8810292b7010 ffff88102618bd98
[154982.431404] ffff8810241150b8 ffff8820244adbb0 ffff88101e4c3900 ffff88102618bd80
[154982.431409] Call Trace:
[154982.431422] [<ffffffff817689d9>] schedule+0x29/0x70
[154982.431435] [<ffffffff8129db99>] jbd2_journal_commit_transaction+0x279/0x19b0
[154982.431446] [<ffffffff810b4d70>] ? prepare_to_wait_event+0x100/0x100
[154982.431456] [<ffffffff8107a69b>] ? lock_timer_base.isra.34+0x2b/0x50
[154982.431461] [<ffffffff812a29fb>] kjournald2+0xbb/0x240
[154982.431466] [<ffffffff810b4d70>] ? prepare_to_wait_event+0x100/0x100
[154982.431469] [<ffffffff812a2940>] ? commit_timeout+0x10/0x10
[154982.431477] [<ffffffff81091332>] kthread+0xd2/0xf0
[154982.431483] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[154982.431489] [<ffffffff8176c9bc>] ret_from_fork+0x7c/0xb0
[154982.431494] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[154982.431517] INFO: task kworker/u49:1:16719 blocked for more than 120 seconds.
[154982.431941] Not tainted 3.16.0-34-generic #47~14.04.1-Ubuntu
[154982.432322] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[154982.432798] kworker/u49:1 D ffff88103fc330c0 0 16719 2 0x00000000
[154982.432810] Workqueue: writeback bdi_writeback_workfn (flush-252:0)
[154982.432813] ffff8810824ab928 0000000000000046 ffff8806eec31460 ffff8810824abfd8
[154982.432817] 00000000000130c0 00000000000130c0 ffff8810292b5bb0 ffff881024115000
[154982.432821] ffff881024115070 00000000000043d0 0000000000000014 ffff88103f66ee10
[154982.432825] Call Trace:
[154982.432829] [<ffffffff817689d9>] schedule+0x29/0x70
[154982.432835] [<ffffffff8129aac9>] wait_transaction_locked+0x79/0xa0
[154982.432840] [<ffffffff810b4d70>] ? prepare_to_wait_event+0x100/0x100
[154982.432845] [<ffffffff8129adf0>] start_this_handle+0x280/0x5a0
[154982.432853] [<ffffffff811b7642>] ? kmem_cache_alloc+0x1b2/0x1e0
[154982.432858] [<ffffffff8129b2b0>] ? jbd2__journal_start+0x90/0x1e0
[154982.432863] [<ffffffff8129b313>] jbd2__journal_start+0xf3/0x1e0
[154982.432869] [<ffffffff81257e9c>] ? ext4_writepages+0x3ac/0xd00
[154982.432873] [<ffffffff81282859>] __ext4_journal_start_sb+0x69/0xe0
[154982.432877] [<ffffffff81257e9c>] ext4_writepages+0x3ac/0xd00
[154982.432882] [<ffffffff810ade48>] ? update_group_capacity+0x28/0x270
[154982.432890] [<ffffffff8116d6ee>] do_writepages+0x1e/0x40
[154982.432895] [<ffffffff811fc360>] __writeback_single_inode+0x40/0x220
[154982.432899] [<ffffffff811fce57>] writeback_sb_inodes+0x247/0x3e0
[154982.432904] [<ffffffff811fd08f>] __writeback_inodes_wb+0x9f/0xd0
[154982.432908] [<ffffffff811fd303>] wb_writeback+0x243/0x2c0
[154982.432912] [<ffffffff811ffa92>] bdi_writeback_workfn+0x2a2/0x430
[154982.432918] [<ffffffff8108a322>] process_one_work+0x182/0x450
[154982.432921] [<ffffffff8108aa91>] worker_thread+0x121/0x570
[154982.432925] [<ffffffff8108a970>] ? rescuer_thread+0x380/0x380
[154982.432930] [<ffffffff81091332>] kthread+0xd2/0xf0
[154982.432935] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[154982.432940] [<ffffffff8176c9bc>] ret_from_fork+0x7c/0xb0
[154982.432944] [<ffffffff81091260>] ? kthread_create_on_node+0x1c0/0x1c0
[155009.500883] qemu-system-x86[14639]: segfault at 20 ip 00007f83263736b9 sp 00007f8307ffe910 error 4 in qemu-system-x86_64[7f8326135000+4af000]
[159660.029412] br0: port 2(vnet0) entered disabled state
[159660.029912] device vnet0 left promiscuous mode
[159660.029917] br0: port 2(vnet0) entered disabled state
[159660.616993] audit: type=1400 audit(1429349837.758:59): apparmor="STATUS" operation="profile_remove" profile="unconfined" name="libvirt-5f30259a-4f7e-a77a-556d-faf3b39bb5de" pid=16981 comm="apparmor_parser"