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Bug 623552 - SCP image fails from host to guest with vhost on when do migration
Summary: SCP image fails from host to guest with vhost on when do migration
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: qemu-kvm
Version: 6.1
Hardware: All
OS: Linux
high
medium
Target Milestone: beta
: 6.1
Assignee: jason wang
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks: Rhel6KvmTier1 642595
TreeView+ depends on / blocked
 
Reported: 2010-08-12 06:18 UTC by juzhang
Modified: 2013-01-09 23:00 UTC (History)
13 users (show)

Fixed In Version: qemu-kvm-0.12.1.2-2.129.el6
Doc Type: Bug Fix
Doc Text:
Cause: bug when syncing the dirty bits of vhost in qemu-kvm Consequence: Some dirty pages may not be transferred to dest host and the scp may fail during migration. Fix: Fix dirty page bit sync code in vhost. Result: scp during migration would not fail anymore.
Clone Of:
Environment:
Last Closed: 2011-05-19 11:26:14 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:0534 0 normal SHIPPED_LIVE Important: qemu-kvm security, bug fix, and enhancement update 2011-05-19 11:20:36 UTC

Description juzhang 2010-08-12 06:18:09 UTC 
Description of problem:
First boot guest in hostA. second,scp a big .qcow image(rhel6.0_2.59_64.qcow2)
to guest.in the process of scp image,do migration from hostA to HostB.Once migration completed,scp failed immediately.

Version-Release number of selected component (if applicable):
Host Kernel and qemu-kvm version
#uname -r 
2.6.32-62.el6.x86_64
#rpm -q qemu-kvm
qemu-kvm-0.12.1.2-2.109.el6.x86_64

Guest kernel
uname -r
#2.6.32-59.1.el6.x86_64


How reproducible:

Steps to Reproduce:
1.Boot guest in HostA
# /usr/libexec/qemu-kvm -m 4G -smp 2 -drive
file=/home/rhel6.0_2.59_64.qcow2,if=none,id=test,boot=on,cache=none,format=qcow2,
werror=stop,rerror=stop -device virtio-blk-pci,drive=test -cpu qemu64,+sse2,+x2apic,-kvmclock -monitor
stdio -drive
file=/root/zhangjunyi/boot.iso,if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw
-device ide-drive,drive=drive-ide0-1-0 -boot order=cdn,menu=on -netdev
tap,id=hostnet0,vhost=on -device
virtio-net-pci,netdev=hostnet0,id=net0,mac=22:11:22:45:66:94 -vnc :10 -qmp
tcp:0:4445,server,nowait


2.Boot listening mode in remote HostB.
#<commandLine> -incoming tcp:0:5555

3.After guest booted,scp rhel6.0_2.59_64.qcow2 from HostA to guest.
#scp rhel6.0_2.59_64.qcow2 10.66.91.95:/root

4.In the process of scp image,do migration from hostA to HostB
#{"execute": "migrate","arguments":{"uri": "tcp:10.66.91.104:5555"}}


Actual results:
Once migration completed,we will see the following messages.
#scp rhel6.0_2.59_64.qcow2 10.66.91.186:/root/
root.91.186's password: 
rhel6.0_2.59_64.qcow2                                                          
                                            29%  541MB   2.5MB/s   08:49
ETAReceived disconnect from 10.66.91.186: 2: Packet corrupt
lost connection

We can reconnect the guest after scp failed.we can do this command again
#scp rhel6.0_2.59_64.qcow2 10.66.91.186:/root/
root.91.186's password: 
rhel6.0_2.59_64.qcow2                                                          
                                            16%  304MB  44.2MB/s   00:35 ETA

Expected results:
scp big file from host to guest successful when do migration. 


Additional info:
Please note the following message
1.If we set vhost=off.command "scp rhel6.0_2.59_64.qcow2 10.66.91.186:/root/"
can completed successful.this is issue only hit when vhost=on.

2.If no migration,we just execute "scp rhel6.0_2.59_64.qcow2
10.66.91.186:/root/".both can completed successful whatever vhost=on/vhost=off.
Comment 3 Alex Williamson 2010-08-30 18:12:36 UTC 
I suspect this problem occurs because the vhost device is not stopped until the virtio-net save routine is called.  At this point a final dirty bitmap sync is done with the kernel, but qemu has already done it's final rounds of syncing dirty pages, so these changes are lost.  Re-assigning to Michael to resolve.
Comment 6 Michael S. Tsirkin 2010-10-27 11:00:25 UTC 
If the issue happens after migration, try
ae8894c00b560bde4cbbc2115f532df997e15d14

git://git.kernel.org/pub/scm/virt/kvm/kvm.git
Comment 7 Michael S. Tsirkin 2010-11-04 05:03:03 UTC 
Try this kernel build
https://brewweb.devel.redhat.com/taskinfo?taskID=2861817
if this fixes the issue it's a kernel bug same as 647367.
Comment 8 Michael S. Tsirkin 2010-11-04 13:33:13 UTC 
Additionally, please try running with sndbuf=0 option for tap,
to check whether this is the issue of packets sent after
migration confusing the bridge.
Comment 14 juzhang 2011-01-24 01:24:35 UTC 
Verified on on qemu-kvm-0.12.1.2-2.129.el6.x86_64,tested two times using steps as same as comment0,didn't hit this issue.this issue has been fixed.
Comment 16 jason wang 2011-05-05 09:43:17 UTC 
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Cause: bug when syncing the dirty bits of vhost in qemu-kvm

Consequence: Some dirty pages may not be transferred to dest host and the scp may fail during migration.

Fix: Fix dirty page bit sync code in vhost.

Result: scp during migration would not fail anymore.
Comment 17 errata-xmlrpc 2011-05-19 11:26:14 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0534.html
Comment 18 errata-xmlrpc 2011-05-19 12:46:57 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0534.html
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