Bug 1540003 - Postcopy migration failed with "Unreasonably large packaged state"
Summary: Postcopy migration failed with "Unreasonably large packaged state"
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm-rhev
Version: 7.5
Hardware: ppc64le
OS: Linux
Target Milestone: rc
: 7.5
Assignee: Laurent Vivier
QA Contact: xianwang
Keywords: Patch
Depends On:
Blocks: 1399177 1476742 1539427
TreeView+ depends on / blocked
Reported: 2018-01-30 03:35 UTC by xianwang
Modified: 2018-05-16 09:13 UTC (History)
13 users (show)

Clone Of:
Last Closed: 2018-04-11 00:58:52 UTC

Attachments (Terms of Use)

External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2018:1104 normal SHIPPED_LIVE Important: qemu-kvm-rhev security, bug fix, and enhancement update 2018-04-10 22:54:38 UTC
IBM Linux Technology Center 164469 None None None 2018-12-25 16:06 UTC

Description xianwang 2018-01-30 03:35:25 UTC
Description of problem:
Postcopy migration from p8 to p9, after switch to postcopy mode, qemu of source side quit automatically with "qemu-kvm: block/io.c:1557: bdrv_co_pwritev: Assertion `!(bs->open_flags & 0x0800)' failed."

Version-Release number of selected component (if applicable):
HostA p8 (RHEL7.5):

HostB p9 (RHEL7.5-alt):

Compose: RHEL-7.5-20171107.1

How reproducible:

Steps to Reproduce:
1.Boot a guest on power8 host, the detail qemu cli is as additional info
2.Launch listening mode on power9 host, the difference of qemu cli between p8 and p9 is: -machine pseries-rhel7.5.0,max-cpu-compat=power8; -incoming tcp:0:5801
3.Do migration from p8 to p9 and switch to postcopy mode
(qemu) migrate_set_capability postcopy-ram on
(qemu) migrate -d tcp:
(qemu) migrate_start_postcopy

Actual results:
migration failed, qemu on both sides quit automatically with error message

on src:
(qemu) qemu-kvm: qemu_savevm_send_packaged: Unreasonably large packaged state: 20771356
qemu-kvm: block/io.c:1557: bdrv_co_pwritev: Assertion `!(bs->open_flags & 0x0800)' failed.
stable2_p8_p9.sh: line 61: 125579 Aborted                 /usr/libexec/qemu-kvm -name 'avocado-vt-vm1'...........

on dst:
(qemu) qemu-kvm: load of migration failed: Input/output error

Expected results:
migration complete and vm works well

Additional info:
qemu cli of p9:
/usr/libexec/qemu-kvm \
-name 'avocado-vt-vm1' \
-sandbox off \
-machine pseries-rhel7.5.0,max-cpu-compat=power8 \
-nodefaults \
-vga std \
-device spapr-pci-host-bridge,index=1   \
-device virtio-scsi-pci,bus=pci.1,id=scsi0,addr=0x3 \
-drive  file=/home/xianwang/mount_point/d1.raw,if=none,id=drive-scsi0-0-0-0,format=raw,cache=none  \
-device  scsi-hd,bus=scsi0.0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,channel=0,scsi-id=0,lun=0   \
-device  virtio-serial-pci,disable-legacy=on,disable-modern=off,id=agent-virtio-serial0,max_ports=16,vectors=0,bus=pci.1,addr=0x4,ioeventfd=on  \
-chardev socket,id=charchannel1,path=/home/channel1,server,nowait  \
-device virtserialport,bus=agent-virtio-serial0.0,nr=3,chardev=charchannel1,id=channel1,name=org.qemu.guest_agent.0 \
-device spapr-pci-host-bridge,index=2  \
-drive  file=/home/xianwang/mount_point/d2.qcow2,id=drive_blk,format=qcow2,if=none,cache=none,werror=stop,rerror=stop \
-device virtio-blk-pci,drive=drive_blk,id=device_blk,multifunction=on,bus=pci.2,addr=0x03.0 \
-device virtio-scsi-pci,id=scsi1,multifunction=on,bus=pci.2,addr=0x03.1 \
-drive  file=/home/xianwang/mount_point/d3.raw,if=none,id=drive-data0,format=raw,cache=none,aio=native  \
-device  scsi-hd,drive=drive-data0,id=data0,bus=scsi1.0,channel=0,scsi-id=0,lun=1 \
-device virtio-serial-pci,id=virtio-serial0,max_ports=32 \
-chardev socket,id=channel1,path=/tmp/helloworld0,server,nowait \
-device  virtserialport,chardev=channel1,name=com.redhat.rhevm.vdsm,bus=virtio-serial0.0,id=port0 \
-chardev socket,id=serial_id_serial0,path=/tmp/console0,server,nowait \
-device spapr-vty,reg=0x30000000,chardev=serial_id_serial0 \
-object rng-random,filename=/dev/random,id=passthrough-rOXjKxaC \
-device virtio-rng-pci,id=virtio-rng-pci-GVn8yzUA,rng=passthrough-rOXjKxaC,bus=pci.0,addr=0x04 \
-device nec-usb-xhci,id=usb1,bus=pci.0,addr=0x05 \
-device pci-ohci,id=usb3,bus=pci.0,addr=0x06 \
-device pci-bridge,id=pci_bridge_1,bus=pci.0,addr=0xc,chassis_nr=1 \
-device pci-bridge,id=pci_bridge_2,bus=pci.0,addr=0xd,chassis_nr=2 \
-object iothread,id=iothread0 \
-device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pci_bridge_1,iothread=iothread0,addr=0x07 \
-device virtio-scsi-pci,id=virtio_scsi_pci1,bus=pci.0,addr=0x08 \
-drive id=drive_image1,if=none,snapshot=off,aio=threads,cache=none,format=qcow2,file=/home/xianwang/mount_point/rhel75-ppc64le-virtio-scsi.qcow2 \
-device scsi-hd,id=image1,drive=drive_image1,bus=virtio_scsi_pci0.0,channel=0,scsi-id=0,lun=0,bootindex=0 \
-drive file=/home/xianwang/mount_point/d4.qcow2,format=qcow2,if=none,cache=none,id=drive_plane,werror=stop,rerror=stop \
-device virtio-blk-pci,drive=drive_plane,id=plane,bus=pci_bridge_2,addr=0x09,iothread=iothread0 \
-drive file=/home/xianwang/mount_point/d5.qcow2,if=none,id=drive-system-disk,format=qcow2,cache=none,aio=native,werror=stop,rerror=stop \
-device spapr-vscsi,reg=0x1000,id=scsi3 \
-device scsi-hd,drive=drive-system-disk,id=system-disk,bus=scsi3.0,channel=0,scsi-id=0,lun=0 \
-drive id=drive_cd1,if=none,snapshot=off,aio=threads,cache=none,media=cdrom,file=/home/xianwang/mount_point/RHEL-7.5-20171215.0-Server-ppc64le-dvd1.iso \
-device scsi-cd,id=cd1,drive=drive_cd1,bus=virtio_scsi_pci1.0,channel=0,scsi-id=0,lun=0,bootindex=1 \
-device virtio-net-pci,mac=9a:4f:50:51:52:53,id=id9HRc5V,netdev=idjlQN53,vectors=10,mq=on,status=on,bus=pci.0,addr=0xa \
-netdev tap,id=idjlQN53,vhost=on,queues=4,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown \
-device spapr-vlan,mac=9a:4f:50:51:52:54,netdev=hostnet0,id=net0 \
-netdev tap,id=hostnet0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown \
-m 4G,slots=4,maxmem=32G \
-smp 8,cores=4,threads=1,sockets=2 \
-device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1 \
-device usb-mouse,id=input1,bus=usb1.0,port=2 \
-device usb-kbd,id=input2,bus=usb1.0,port=3 \
-vnc :2 \
-incoming tcp:0:5801 \
-qmp tcp:0:8881,server,nowait \
-monitor stdio \
-rtc base=utc,clock=host \
-boot order=cdn,once=c,menu=on,strict=on \
-enable-kvm \
-watchdog i6300esb \
-watchdog-action reset \
-device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xb \

Comment 2 Laurent Vivier 2018-01-30 10:40:19 UTC
The real problem is "Unreasonably large packaged state", the second error message is another bug triggered by the first problem.

This problem is addressed by:

"migration/savevm.c: set MAX_VM_CMD_PACKAGED_SIZE to 1ul << 32"

Comment 3 Laurent Vivier 2018-01-30 10:41:34 UTC
This problem should not be related to P9. Could you test the migration between two P8 hosts (with the same command line)?

Comment 4 Daniel Henrique Barboza 2018-01-30 14:12:19 UTC
I've faced this problem in a different scenario, P9->P9 migration, using a pseries guest with few devices but lots of RAM (128Gb+). When starting the postcopy migration, QEMU sends a single blob with the entire device state of the guest to the destination. This blob has a maximum size of 16 megabytes. If the blob turns out to be larger than that (which is the case here: 20771356 is 20MB) QEMU aborts the sending and migration fails on both sides.

This happens in the migration code with all architectures, it is not a P9 exclusive behaviour. Thus, as Laurent mentioned in comment #3, you should be able to reproduce it in a P8->P8 scenario too.

Comment 6 xianwang 2018-01-31 07:55:46 UTC
(In reply to Laurent Vivier from comment #3)
> This problem should not be related to P9. Could you test the migration
> between two P8 hosts (with the same command line)?

Yes, I have tried the postcopy migration(same as bug report) between two p8 hosts with the same command line, the result is same with this bug, the version is as following:


Comment 9 David Gibson 2018-02-12 01:13:07 UTC
Blocker justification:

1) Migration, including post-copy, is a primary feature we intend to support for POWER KVM guests.

2) This bug could trip on essentially any post-copy migration, there's no simple way for a user to work around the problem.

3) The fix is extremely simple - simply changing a single limit value within qemu.

Comment 12 Miroslav Rezanina 2018-02-20 13:43:32 UTC
Fix included in qemu-kvm-rhev-2.10.0-21.el7

Comment 14 Qunfang Zhang 2018-02-22 07:05:32 UTC
This bug could be reproduced with qemu-kvm-rhev-2.10.0-20.el7. I tried both P8 <-> P8 and P8 -> P9 with the same steps and comment line as comment 0.  

After start postcopy migration, I hit the errors:

src host:

(qemu) qemu-kvm: block/io.c:1557: bdrv_co_pwritev: Assertion `!(bs->open_flags & 0x0800)' failed.
Aborted (core dumped)

dst host:
(qemu) qemu-kvm: load of migration failed: Input/output error

Verified this bug with qemu-kvm-rhev-2.10.0-21.el7, the issue doesn't exist any more. Migration finishes successfully with the original command line and steps. 

I'll set the status to VERIFIED, if some more testing required, please let me know.

Besides, since there are multiple migration bugs got fixed recently, we'll conduct migration function test on both Power8 and Power9 for regression purpose.

Comment 16 errata-xmlrpc 2018-04-11 00:58:52 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


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