Qemu hangs during migration

Source server: linux 4.19.5 qemu-3.0.0 from source, libvirt 4.9
Dest server: linux 4.18.19 qemu-3.0.0 from source, libvirt 4.9

When this VM is running on source server:

/usr/bin/qemu-system-x86_64 -name guest=testvm,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-13-testvm/master-key.aes -machine pc-q35-3.0,accel=kvm,usb=off,dump-guest-core=off -cpu Skylake-Server-IBRS,ss=on,hypervisor=on,tsc_adjust=on,clflushopt=on,umip=on,pku=on,ssbd=on,xsaves=on,topoext=on,hv_time,hv_relaxed,hv_vapic,hv_spinlocks=0x1fff,hv_vpindex,hv_runtime,hv_synic,hv_stimer,hv_reset,hv_vendor_id=KVM Hv -m 4096 -realtime mlock=off -smp 2,sockets=2,cores=1,threads=1 -object iothread,id=iothread1 -uuid 3b00b788-ee91-4e45-80a6-c7319da71225 -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=23,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -boot strict=on -device pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2 -device pcie-root-port,port=0x11,chassis=2,id=pci.2,bus=pcie.0,addr=0x2.0x1 -device pcie-pci-bridge,id=pci.3,bus=pci.1,addr=0x0 -device pcie-root-port,port=0x12,chassis=4,id=pci.4,bus=pcie.0,addr=0x2.0x2 -device pcie-root-port,port=0x13,chassis=5,id=pci.5,bus=pcie.0,addr=0x2.0x3 -device piix3-usb-uhci,id=usb,bus=pci.3,addr=0x1 -device virtio-scsi-pci,iothread=iothread1,id=scsi0,bus=pci.4,addr=0x0 -drive file=/dev/zvol/datastore/vm/testvm-vda,format=raw,if=none,id=drive-scsi0-0-0-0,cache=writeback,aio=threads -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=2,write-cache=on -drive if=none,id=drive-sata0-0-4,media=cdrom,readonly=on -device ide-cd,bus=ide.4,drive=drive-sata0-0-4,id=sata0-0-4,bootindex=1 -netdev tap,fd=25,id=hostnet0,vhost=on,vhostfd=26 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:a2:b7:a1,bus=pci.2,addr=0x0 -device usb-tablet,id=input0,bus=usb.0,port=1 -vnc 127.0.0.1:0 -device cirrus-vga,id=video0,bus=pcie.0,addr=0x1 -s -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on

I try to migrate it and the disks to the other side:

virsh migrate --live --undefinesource --persistent --verbose --copy-storage-all testvm qemu+ssh://wasvirt1/system

We get to 99% then hang with both sides in the pause state.

Source server is stuck here:
(gdb) bt full
#0  0x00007f327994f3c1 in ppoll () at /lib64/libc.so.6
#1  0x000000000086167b in qemu_poll_ns (fds=<optimized out>, nfds=nfds@entry=1, timeout=<optimized out>) at util/qemu-timer.c:322
#2  0x0000000000863302 in aio_poll (ctx=0x21044e0, blocking=blocking@entry=true) at util/aio-posix.c:629
        node = <optimized out>
        i = <optimized out>
        ret = 0
        progress = <optimized out>
        timeout = <optimized out>
        start = <optimized out>
        __PRETTY_FUNCTION__ = "aio_poll"
#3  0x00000000007e0d52 in nbd_client_close (bs=0x2ba2400) at block/nbd-client.c:62
        waited_ = <optimized out>
        wait_ = 0x2ba563c
        ctx_ = 0x2109bb0
        bs_ = 0x2ba2400
        client = 0x31287e0
        client = <optimized out>
        request = {handle = 0, from = 0, len = 0, flags = 0, type = 2}
#4  0x00000000007e0d52 in nbd_client_close (bs=0x2ba2400) at block/nbd-client.c:965
        client = <optimized out>
        request = {handle = 0, from = 0, len = 0, flags = 0, type = 2}
#5  0x00000000007de5ca in nbd_close (bs=<optimized out>) at block/nbd.c:491
        s = 0x31287e0
#6  0x00000000007823d6 in bdrv_unref (bs=0x2ba2400) at block.c:3352
        ban = <optimized out>
        ban_next = <optimized out>
        child = <optimized out>
        next = <optimized out>
#7  0x00000000007823d6 in bdrv_unref (bs=0x2ba2400) at block.c:3560
#8  0x00000000007823d6 in bdrv_unref (bs=0x2ba2400) at block.c:4616
#9  0x0000000000782403 in bdrv_unref (bs=0x2af96f0) at block.c:3359
        ban = <optimized out>
        ban_next = <optimized out>
        child = <optimized out>
        next = <optimized out>
#10 0x0000000000782403 in bdrv_unref (bs=0x2af96f0) at block.c:3560
#11 0x0000000000782403 in bdrv_unref (bs=0x2af96f0) at block.c:4616
#12 0x0000000000785784 in block_job_remove_all_bdrv (job=job@entry=0x2f32570) at blockjob.c:200
        c = 0x23bac30
        l = 0x20dd330 = {0x23bac30, 0x2b89410}
#13 0x00000000007ceb5f in mirror_exit (job=0x2f32570, opaque=0x7f326407a350) at block/mirror.c:700
        s = 0x2f32570
        bjob = 0x2f32570
        data = 0x7f326407a350
        bs_opaque = 0x30d5600
        replace_aio_context = <optimized out>
        src = 0x2131080
        target_bs = 0x2af96f0
        mirror_top_bs = 0x210eb70
        local_err = 0x0
#14 0x0000000000786452 in job_defer_to_main_loop_bh (opaque=0x7f32640786a0) at job.c:973
        data = 0x7f32640786a0
        job = <optimized out>
        aio_context = 0x2109bb0
#15 0x000000000085fd3f in aio_bh_poll (ctx=ctx@entry=0x21044e0) at util/async.c:118
---Type <return> to continue, or q <return> to quit---
        bh = <optimized out>
        bhp = <optimized out>
        next = 0x2ea86e0
        ret = 1
        deleted = false
#16 0x00000000008631b0 in aio_dispatch (ctx=0x21044e0) at util/aio-posix.c:436
#17 0x000000000085fc1e in aio_ctx_dispatch (source=<optimized out>, callback=<optimized out>, user_data=<optimized out>) at util/async.c:261
        ctx = <optimized out>
#18 0x00007f327f17d797 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#19 0x00000000008622ed in main_loop_wait () at util/main-loop.c:215
        context = 0x2104900
        pfds = <optimized out>
        context = 0x2104900
        ret = 1
        ret = 1
        timeout = 4294967295
        timeout_ns = <optimized out>
#20 0x00000000008622ed in main_loop_wait (timeout=<optimized out>) at util/main-loop.c:238
        context = 0x2104900
        ret = 1
        ret = 1
        timeout = 4294967295
        timeout_ns = <optimized out>
#21 0x00000000008622ed in main_loop_wait (nonblocking=nonblocking@entry=0) at util/main-loop.c:497
        ret = 1
        timeout = 4294967295
        timeout_ns = <optimized out>
#22 0x0000000000595dee in main_loop () at vl.c:1866
#23 0x000000000041f35d in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4644
        i = <optimized out>
        snapshot = 0
        linux_boot = <optimized out>
        initrd_filename = 0x0
        kernel_filename = <optimized out>
        kernel_cmdline = <optimized out>
        boot_order = 0x918f44 "cad"
        boot_once = 0x0
        ds = <optimized out>
        opts = <optimized out>
        machine_opts = <optimized out>
        icount_opts = <optimized out>
        accel_opts = 0x0
        olist = <optimized out>
        optind = 71
        optarg = 0x7ffdfc94df69 "timestamp=on"
        loadvm = 0x0
        machine_class = 0x0
        cpu_model = 0x7ffdfc94d864 "Skylake-Server-IBRS,ss=on,hypervisor=on,tsc_adjust=on,clflushopt=on,umip=on,pku=on,ssbd=on,xsaves=on,topoext=on,hv_time,hv_relaxed,hv_vapic,hv_spinlocks=0x1fff,hv_vpindex,hv_runtime,hv_synic,hv_stimer"...
        vga_model = 0x0
        qtest_chrdev = 0x0
        qtest_log = 0x0
        pid_file = <optimized out>
        incoming = 0x0
        userconfig = <optimized out>
---Type <return> to continue, or q <return> to quit---
        nographic = false
        display_remote = <optimized out>
        log_mask = <optimized out>
        log_file = <optimized out>
        trace_file = <optimized out>
        maxram_size = 4294967296
        ram_slots = 0
        vmstate_dump_file = 0x0
        main_loop_err = 0x0
        err = 0x0
        list_data_dirs = false
        dir = <optimized out>
        dirs = <optimized out>
        bdo_queue = {sqh_first = 0x0, sqh_last = 0x7ffdfc94c170}
        __func__ = "main"

Strace shows:
ppoll([{fd=9, events=POLLIN|POLLERR|POLLHUP}], 1, NULL, NULL, 8

Which points to this:

ls -al /proc/2286/fd/9
lrwx------    1 root     users           64 Dec  5 13:04 /proc/2286/fd/9 -> anon_inode:[eventfd]

The dest side is stuck here:

(gdb) bt full
#0  0x00007f21f070d3c1 in ppoll () at /lib64/libc.so.6
#1  0x0000000000861659 in qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>, timeout=timeout@entry=2999926258) at util/qemu-timer.c:334
        ts = {tv_sec = 2, tv_nsec = 999926258}
Python Exception <class 'gdb.error'> That operation is not available on integers of more than 8 bytes.:
#2  0x00000000008622a4 in main_loop_wait (timeout=<optimized out>) at util/main-loop.c:233
        context = 0x2142900
        ret = <optimized out>
        ret = -1295041038
        timeout = 4294967295
        timeout_ns = <optimized out>
#3  0x00000000008622a4 in main_loop_wait (nonblocking=nonblocking@entry=0) at util/main-loop.c:497
        ret = -1295041038
        timeout = 4294967295
        timeout_ns = <optimized out>
#4  0x0000000000595dee in main_loop () at vl.c:1866
#5  0x000000000041f35d in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4644
        i = <optimized out>
        snapshot = 0
        linux_boot = <optimized out>
        initrd_filename = 0x0
        kernel_filename = <optimized out>
        kernel_cmdline = <optimized out>
        boot_order = 0x918f44 "cad"
        boot_once = 0x0
        ds = <optimized out>
        opts = <optimized out>
        machine_opts = <optimized out>
        icount_opts = <optimized out>
        accel_opts = 0x0
        olist = <optimized out>
        optind = 73
        optarg = 0x7ffdd6ee8f69 "timestamp=on"
        loadvm = 0x0
        machine_class = 0x0
        cpu_model = 0x7ffdd6ee8854 "Skylake-Server-IBRS,ss=on,hypervisor=on,tsc_adjust=on,clflushopt=on,umip=on,pku=on,ssbd=on,xsaves=on,topoext=on,hv_time,hv_relaxed,hv_vapic,hv_spinlocks=0x1fff,hv_vpindex,hv_runtime,hv_synic,hv_stimer"...
        vga_model = 0x0
        qtest_chrdev = 0x0
        qtest_log = 0x0
        pid_file = <optimized out>
        incoming = 0x7ffdd6ee8f0a "defer"
        userconfig = <optimized out>
        nographic = false
        display_remote = <optimized out>
        log_mask = <optimized out>
        log_file = <optimized out>
        trace_file = <optimized out>
        maxram_size = 4294967296
        ram_slots = 0
        vmstate_dump_file = 0x0
        main_loop_err = 0x0
        err = 0x0
        list_data_dirs = false
        dir = <optimized out>
        dirs = <optimized out>
        bdo_queue = {sqh_first = 0x0, sqh_last = 0x7ffdd6ee6630}
---Type <return> to continue, or q <return> to quit---
        __func__ = "main"

Strace show this over and over
ppoll([{fd=6, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9, events=POLLIN}, {fd=10, events=POLLIN}, {fd=21, events=POLLIN}, {fd=22, events=POLLIN}, {fd=23, events=POLLIN}, {fd=24, events=POLLIN}, {fd=27, events=POLLIN}], 9, {0, 594527977}, NULL, 8) = 0 (Timeout)

lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/10 -> anon_inode:[eventfd]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/21 -> socket:[42631161]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/22 -> socket:[42631165]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/23 -> socket:[42631167]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/24 -> socket:[42631168]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/27 -> socket:[42690422]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/6 -> anon_inode:[eventfd]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/7 -> anon_inode:[signalfd]
lrwx------    1 root     users           64 Dec  5 13:15 /proc/20170/fd/9 -> anon_inode:[eventfd]