qemu 8.1.1 and 7.2.6 live migration with qcow2 attached to vm using postcopy crashes

Host environment

• Operating system: Fedora 38
• OS/kernel version: Linux 6.1.55-1.phys.x86_64 #1 SMP Sat Sep 23 10:11:25 PDT 2023 x86_64 GNU/Linux
• QEMU flavor: qemu-system-x86_64
• QEMU version: 8.1.1 and 7.2.6
• QEMU command line: /usr/bin/qemu-system-x86_64 -name guest=jlow2,debug-threads=on -S -object {"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain-4-jlow2/master-key.aes"} -machine pc-q35-8.1,usb=off,vmport=off,dump-guest-core=off,memory-backend=pc.ram,acpi=on -accel kvm -cpu SandyBridge-IBRS,vme=on,hypervisor=on,arat=on,xsaveopt=on,kvmclock=on,kvm-pv-unhalt=on -m size=8388608k -object {"qom-type":"memory-backend-ram","id":"pc.ram","size":8589934592} -overcommit mem-lock=off -smp 2,sockets=2,cores=1,threads=1 -uuid a9d77c64-d821-4171-a41a-bb770476b3ba -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=22,server=on,wait=off -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -global ICH9-LPC.disable_s3=1 -global ICH9-LPC.disable_s4=1 -boot menu=off,strict=on -device {"driver":"pcie-root-port","port":16,"chassis":1,"id":"pci.1","bus":"pcie.0","multifunction":true,"addr":"0x2"} -device {"driver":"pcie-root-port","port":17,"chassis":2,"id":"pci.2","bus":"pcie.0","addr":"0x2.0x1"} -device {"driver":"pcie-root-port","port":18,"chassis":3,"id":"pci.3","bus":"pcie.0","addr":"0x2.0x2"} -device {"driver":"pcie-root-port","port":19,"chassis":4,"id":"pci.4","bus":"pcie.0","addr":"0x2.0x3"} -device {"driver":"pcie-root-port","port":20,"chassis":5,"id":"pci.5","bus":"pcie.0","addr":"0x2.0x4"} -device {"driver":"pcie-root-port","port":21,"chassis":6,"id":"pci.6","bus":"pcie.0","addr":"0x2.0x5"} -device {"driver":"pcie-root-port","port":22,"chassis":7,"id":"pci.7","bus":"pcie.0","addr":"0x2.0x6"} -device {"driver":"pcie-root-port","port":23,"chassis":8,"id":"pci.8","bus":"pcie.0","addr":"0x2.0x7"} -device {"driver":"pcie-root-port","port":24,"chassis":9,"id":"pci.9","bus":"pcie.0","multifunction":true,"addr":"0x3"} -device {"driver":"pcie-root-port","port":25,"chassis":10,"id":"pci.10","bus":"pcie.0","addr":"0x3.0x1"} -device {"driver":"pcie-root-port","port":26,"chassis":11,"id":"pci.11","bus":"pcie.0","addr":"0x3.0x2"} -device {"driver":"pcie-root-port","port":27,"chassis":12,"id":"pci.12","bus":"pcie.0","addr":"0x3.0x3"} -device {"driver":"pcie-root-port","port":28,"chassis":13,"id":"pci.13","bus":"pcie.0","addr":"0x3.0x4"} -device {"driver":"pcie-root-port","port":29,"chassis":14,"id":"pci.14","bus":"pcie.0","addr":"0x3.0x5"} -device {"driver":"qemu-xhci","p2":15,"p3":15,"id":"usb","bus":"pci.2","addr":"0x0"} -device {"driver":"virtio-serial-pci","id":"virtio-serial0","bus":"pci.3","addr":"0x0"} -blockdev {"driver":"file","filename":"/var/lib/libvirt/images/jlow2.qcow2","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-1-format","read-only":false,"cache":{"direct":true,"no-flush":false},"driver":"qcow2","file":"libvirt-1-storage","backing":null} -device {"driver":"virtio-blk-pci","bus":"pci.5","addr":"0x0","drive":"libvirt-1-format","id":"virtio-disk0","bootindex":1,"write-cache":"on"} -netdev {"type":"tap","fd":"23","vhost":true,"vhostfd":"25","id":"hostnet0"} -device {"driver":"virtio-net-pci","netdev":"hostnet0","id":"net0","mac":"52:54:00:b2:e4:17","bootindex":10,"bus":"pci.1","addr":"0x0","rombar":1} -chardev pty,id=charserial0 -device {"driver":"isa-serial","chardev":"charserial0","id":"serial0","index":0} -chardev socket,id=charchannel0,fd=21,server=on,wait=off -device {"driver":"virtserialport","bus":"virtio-serial0.0","nr":1,"chardev":"charchannel0","id":"channel0","name":"org.qemu.guest_agent.0"} -chardev spicevmc,id=charchannel1,name=vdagent -device {"driver":"virtserialport","bus":"virtio-serial0.0","nr":2,"chardev":"charchannel1","id":"channel1","name":"com.redhat.spice.0"} -device {"driver":"usb-tablet","id":"input0","bus":"usb.0","port":"1"} -audiodev {"id":"audio1","driver":"spice"} -spice port=5900,addr=0.0.0.0,disable-ticketing=on,image-compression=off,seamless-migration=on -device {"driver":"virtio-vga","id":"video0","max_outputs":1,"bus":"pcie.0","addr":"0x1"} -global ICH9-LPC.noreboot=off -watchdog-action none -chardev spicevmc,id=charredir0,name=usbredir -device {"driver":"usb-redir","chardev":"charredir0","id":"redir0","bus":"usb.0","port":"2"} -chardev spicevmc,id=charredir1,name=usbredir -device {"driver":"usb-redir","chardev":"charredir1","id":"redir1","bus":"usb.0","port":"3"} -incoming defer -object {"qom-type":"rng-random","id":"objrng0","filename":"/dev/urandom"} -device {"driver":"virtio-rng-pci","rng":"objrng0","id":"rng0","bus":"pci.4","addr":"0x0"} -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on

Description of problem

Live migrating a vm with a qcow2 disk attached using postcopy will cause vm to crash during migration.

Steps to reproduce

1. Create a generic vm and attach a qcow2 file to the vm.

2. virsh migrate jlow2 --change-protection --persistent --live --verbose --undefinesource --abort-on-error --postcopy --postcopy-after-precopy --timeout 1 --timeout-postcopy qemu+tcp://10.18.64.118/system

vm will start migrating and then pause on the source and be shut down on the target once migration switches to postcopy

Migration: [33.08 %]error: internal error: QEMU unexpectedly closed the monitor (vm='jlow2'): 2023-10-12T06:23:44.354387Z qemu-system-x86_64: warning: TSC frequency mismatch between VM (2892749 kHz) and host (2799999 kHz), and TSC scaling unavailable 2023-10-12T06:23:44.354538Z qemu-system-x86_64: warning: TSC frequency mismatch between VM (2892749 kHz) and host (2799999 kHz), and TSC scaling unavailable qemu-system-x86_64: ../block/qcow2.c:5257: qcow2_get_specific_info: Assertion `false' failed.

Logs from source

2023-10-12 06:23:43.412+0000: initiating migration

2023-10-12T06:23:44.362392Z qemu-system-x86_64: failed to save SaveStateEntry with id(name): 3(ram): -5

2023-10-12T06:23:44.362485Z qemu-system-x86_64: Detected IO failure for postcopy. Migration paused.

Logs from target

2023-10-12T06:23:44.354387Z qemu-system-x86_64: warning: TSC frequency mismatch between VM (2892749 kHz) and host (2799999 kHz), and TSC scaling unavailable

2023-10-12T06:23:44.354538Z qemu-system-x86_64: warning: TSC frequency mismatch between VM (2892749 kHz) and host (2799999 kHz), and TSC scaling unavailable

qemu-system-x86_64: ../block/qcow2.c:5257: qcow2_get_specific_info: Assertion `false' failed. 2023-10-12 06:23:44.408+0000: shutting down, reason=failed

If postcopy is disabled with command below, migration will succeed:

virsh migrate jlow2 --change-protection --persistent --live --verbose --undefinesource --abort-on-error qemu+tcp://10.18.64.118/system