cherry-pick segfault fix

cherry-pick segfault fix

this was reported multiple times in our forums[1 with backtraces, 2 & 3
with same log messages], fix is taken from upstream master.

1: https://forum.proxmox.com/threads/pve-7-0-14-1-vm-not-running-live-migration-kills-vm-post-ssd-move-pre-ram-move.99704/
2: https://forum.proxmox.com/threads/proxmox-7-0-14-1-crashes-vm-during-migrate-to-other-host.99678
3: https://forum.proxmox.com/threads/cannot-migrate-between-zfs-and-ceph.99685/#post-430152

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>