Re: [Qemu-discuss] Latest Qemu-COLO Segfaults

[Zhang Chen]

Hi Lukas,

Sorry, I didn't receive the previous email in my gmail.
Currently, COLO not support primary node and secondary node both in one
physical machine.
COLO is a HA solution, in this case can not support physical faults, like
power cuts.
So, you'd better use two physical machine to use COLO, the latest branch:
https://github.com/zhangckid/qemu/tree/qemu-colo-18mar11
By the way, I have tested this case, but I can't got the same Segfaults.
In my side, the primary COLO node get stuck in chardev socket related code,

Thanks
Zhang Chen

On Sun, Mar 18, 2018 at 12:34 AM, Lukas Straub <address@hidden> wrote:

> Hello Everyone,
> Any Status on this?
>
> Kind Regards,
> Lukas Straub
>
> On Sat, 17 Feb 2018 17:36:29 +0100
> Lukas Straub <address@hidden> wrote:
>
> > Hello Mr. Chen,
> > I was trying your latest Version of Qemu-COLO
> > (https://github.com/zhangckid/qemu/tree/qemu-colo-18jan19) with both
> > Qemu Instances running on One Host. However the Secondary always
> > Segfaults after entering the QMP Commands, and Sometimes even the
> > Primary Segfaults, depending on the -cpu Parameter. Everything is
> > working fine when not using COLO.
> >
> > Kind Regards,
> > Lukas Straub
> >
> >
> > Primary Command:
> >
> > ./qemu-system-x86_64 -enable-kvm -cpu host -m 1024 -qmp stdio -name
> > primary -netdev
> > tap,helper=/usr/lib/qemu/qemu-bridge-helper,id=hn0,vhost=off -device
> > virtio-net-pci,id=net-pci0,netdev=hn0 -drive
> > if=virtio,id=primary-disk0,driver=quorum,read-pattern=
> fifo,vote-threshold=1,children.0.file.filename=/mnt/
> vms/colo-test/primary.raw,children.0.driver=raw
> > -S
> >
> >
> > Secondary Command:
> >
> > ./qemu-system-x86_64 -enable-kvm -cpu host -m 1024 -qmp stdio -name
> > secondary -netdev
> > tap,helper=/usr/lib/qemu/qemu-bridge-helper,id=hn0,vhost=off -device
> > virtio-net-pci,id=net-pci0,netdev=hn0 -drive
> > if=none,id=secondary-disk0,file.filename=/mnt/vms/colo-
> test/primary-copy.raw,driver=raw,node-name=node0
> > -drive
> > if=virtio,id=active-disk0,driver=replication,mode=
> secondary,file.driver=qcow2,top-id=active-disk0,file.file.
> filename=/mnt/vms/colo-test/active.qcow2,file.backing.
> driver=qcow2,file.backing.file.filename=/mnt/vms/colo-
> test/hidden.qcow2,file.backing.backing=secondary-disk0
> > -incoming tcp:0:8888
> >
> >
> > 1. Secondary QMP Commands:
> >
> > {'execute':'qmp_capabilities'}
> > { 'execute': 'nbd-server-start',
> >   'arguments': {'addr': {'type': 'inet', 'data': {'host':
> > '127.0.0.1', 'port': '8889'} } } }
> > {'execute': 'nbd-server-add', 'arguments':
> > {'device':'secondary-disk0', 'writable': true } }
> >
> >
> > 2. Primary QMP Commands:
> >
> > {'execute':'qmp_capabilities'}
> > { 'execute': 'human-monitor-command',
> >   'arguments': {'command-line': 'drive_add -n buddy
> > driver=replication,mode=primary,file.driver=nbd,file.
> host=127.0.0.1,file.port=8889,file.export=secondary-disk0,
> node-name=nbd_client0'}}
> > { 'execute':'x-blockdev-change', 'arguments':{'parent':
> > 'primary-disk0', 'node': 'nbd_client0' } } { 'execute':
> > 'migrate-set-capabilities', 'arguments': {'capabilities':
> > [ {'capability': 'x-colo', 'state': true } ] } } { 'execute':
> > 'migrate', 'arguments': {'uri': 'tcp:127.0.0.1:8888' } }
> >
> >
> >
> > Secondary in gdb (without using KVM):
> >
> > Starting
> > program: /home/lukas/lxcshare/build/qemu/x86_64-softmmu/qemu-
> system-x86_64
> > -m 1024 -qmp stdio -name secondary -netdev
> > tap,helper=/usr/lib/qemu/qemu-bridge-helper,id=hn0,vhost=off -device
> > virtio-net-pci,id=net-pci0,netdev=hn0 -drive
> > if=none,id=secondary-disk0,file.filename=/mnt/vms/colo-
> test/primary-copy.raw,driver=raw,node-name=node0
> > -drive
> > if=virtio,id=active-disk0,driver=replication,mode=
> secondary,file.driver=qcow2,top-id=active-disk0,file.file.
> filename=/mnt/vms/colo-test/active.qcow2,file.backing.
> driver=qcow2,file.backing.file.filename=/mnt/vms/colo-
> test/hidden.qcow2,file.backing.backing=secondary-disk0
> > -incoming tcp:0:8888 [Thread debugging using libthread_db enabled]
> > Using host libthread_db library
> > "/lib/x86_64-linux-gnu/libthread_db.so.1". [New Thread 0x7fffedb07700
> > (LWP 24258)] [New Thread 0x7fffdd306700 (LWP 24262)] {"QMP":
> > {"version": {"qemu": {"micro": 50, "minor": 11, "major": 2},
> > "package": " (v2.3.0-20031-g18b5475aba-dirty)"}, "capabilities": []}}
> > [New Thread 0x7fffd7d1c700 (LWP 24269)]
> > {'execute':'qmp_capabilities'} { 'execute': 'nbd-server-start',
> > 'arguments': {'addr': {'type': 'inet', 'data': {'host': '127.0.0.1',
> > 'port': '8889'} } } } {'execute': 'nbd-server-add', 'arguments':
> > {'device': 'secondary-disk0', 'writable': true } }
> >
> > {"return": {}}
> > {"return": {}}
> > [Thread 0x7fffdd306700 (LWP 24262) exited]
> > [New Thread 0x7fffdd306700 (LWP 24462)]
> > [New Thread 0x7fff479ff700 (LWP 24463)]
> > {"timestamp": {"seconds": 1518884676, "microseconds": 286781},
> > "event": "RESUME"}
> >
> > Thread 4 "qemu-system-x86" received signal SIGSEGV, Segmentation
> > fault. [Switching to Thread 0x7fffd7d1c700 (LWP 24269)]
> > qemu_lockcnt_inc (address@hidden) at util/lockcnt.c:113
> > 113     util/lockcnt.c: No such file or directory.
> > (gdb) q
> >
>
>