[Qemu-discuss] Latest Qemu-COLO Segfaults

[Lukas Straub]

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