Re: [Qemu-devel] Block Migration Assertion in qemu-kvm 1.2.0

[Peter Lieven]

On 09/17/12 10:41, Kevin Wolf wrote:
> Am 16.09.2012 12:13, schrieb Peter Lieven:
> > Hi,
> >
> > when trying to block migrate a VM from one node to another, the source
> > VM crashed with the following assertion:
> > block.c:3829: bdrv_set_in_use: Assertion `bs->in_use != in_use' failed.
> >
> > Is this sth already addresses/known?
> Not that I'm aware of, at least.
>
> Block migration doesn't seem to check whether the device is already in
> use, maybe this is the problem. Not sure why it would be in use, though,
> and in my quick test it didn't crash.
It seems that it only happens if a vServer that has been block migrated 
earlier is block migrated the next time.
> So we need some more information: What's you command line, did you do
> anything specific in the monitor with block devices, what does the
> stacktrace look like, etc.?
Here is my cmdline:
/usr/bin/qemu-kvm-1.2.0  -net 
tap,vlan=164,script=no,downscript=no,ifname=tap0  -net nic,vlan
=164,model=e1000,macaddr=52:54:00:ff:01:19   -drive 
format=host_device,file=/dev/7cf58855099771c2/lieven-storage-migration-t-hd0,if=virtio,cache=none,aio=nat
ive  -m 2048 -smp 2,sockets=1,cores=2,threads=1  -monitor 
tcp:0:4001,server,nowait -vnc :1 -qmp tcp:0:3001,server,nowait  -name 
'lieven-storage-migration-test'  -boot or
der=dc,menu=off  -k de  -incoming tcp:172.21.55.34:5001  -pidfile 
/var/run/qemu/vm-254.pid  -mem-path /hugepages  -mem-prealloc  -rtc 
base=utc -usb -usbdevice tablet -no
-hpet -vga cirrus  -cpu host,+x2apic,model_id='Intel(R) Xeon(R) 
CPU           L5640  @ 2.27GHz',-tsc

I have seen other errors as well in the meantime:
block-migration.c:471: flush_blks: Assertion `block_mig_state.read_done 
>= 0' failed.
qemu-kvm-1.2.0[27851]: segfault at 7f00746e78d7 ip 00007f67eca6226d sp 
00007fff56ae3340 error 4 in qemu-system-x86_64[7f67ec9e9000+418000]

I will now try to catch the situation in the debugger.

Thanks,
Peter

> Kevin