Given that the old style storage migration is mostly un maintained, this is unlikely to get fixed. I'd be interested to know if you can trigger a similar assertion with libvirt nbd based storage migration, or the same commands on F20 (since then we can forward the report upstream)
Description of problem: after completing the configuration of src and des, sometimes qemu will be core dump on des Version-Release number of selected component (if applicable): # uname -r 3.9.2-301.fc19.x86_64 qemu-kvm-1.4.1-3.fc19.x86_64 How reproducible: 50% Steps to Reproduce: 1.des host: qemu-img create -f qcow2 test.qcow2 35G qemu-kvm -cpu SandyBridge -M pc-i440fx-1.4 -enable-kvm -m 4G -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection -name scalability-test -uuid 389d06a7-e631-4fae-baf4-87bdb9b5594e -rtc base=localtime,clock=host,driftfix=slew -drive file=/home/test.qcow2,if=none,id=drive-system-disk,media=disk,format=qcow2,aio=native,werror=stop,rerror=stop -device virtio-blk-pci,bus=pci.0,drive=drive-system-disk,id=system-disk,addr=0x6 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device virtio-net-pci,netdev=hostnet0,id=virtio-net-pci0,mac=00:22:15:27:54:3d,bus=pci.0,addr=0x9 -k en-us -boot menu=on -vnc :0 -vga cirrus -monitor stdio -qmp tcp:0:5555,server,nowait -incoming tcp:0:5888 { "execute": "qmp_capabilities" } { "execute": "nbd-server-start", "arguments": { "addr": { "type": "inet", "data": { "host": "10.66.6.154", "port": "8888" } } } } (qemu) nbd_server_add -w drive-system-disk 2.src host: qemu-img info fedora19.qcow2 image: fedora19.qcow2 file format: qcow2 virtual size: 40G (42949672960 bytes) disk size: 16G cluster_size: 65536 qemu-kvm -cpu SandyBridge -M pc-i440fx-1.4 -enable-kvm -m 4G -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection -name scalability-test -uuid 389d06a7-e631-4fae-baf4-87bdb9b5594e -rtc base=localtime,clock=host,driftfix=slew -drive file=/home/fedora19.qcow2,if=none,id=drive-system-disk,media=disk,format=qcow2,aio=native,werror=stop,rerror=stop -device virtio-blk-pci,bus=pci.0,drive=drive-system-disk,id=system-disk,addr=0x6 -netdev tap,id=hostnet0,vhost=on,script=/etc/qemu-ifup -device virtio-net-pci,netdev=hostnet0,id=virtio-net-pci0,mac=00:22:15:27:54:3d,bus=pci.0,addr=0x9 -k en-us -boot menu=on -vnc :0 -vga cirrus -monitor stdio -qmp tcp:0:5555,server,nowait { "execute": "qmp_capabilities" } { "execute": "drive-mirror", "arguments": { "device": "drive-system-disk", "target": "nbd://10.66.6.154:8888/drive-system-disk", "sync": "full", "format": "raw", "mode": "existing" } } 3.migrate -d tcp:$des-host-ip:$port Actual results: des: (qemu) qemu-system-x86_64: block/qcow2-cache.c:67: qcow2_cache_destroy: Assertion `c->entries[i].ref == 0' failed. Expected results: qemu can work normally Additional info: