There are reports of a kernel regression that is causing VirtualBox instability:
- Changes in kernel 5.18-rc1 leads to crashes in VirtualBox Virtual Machines
- FS#74900 : [virtualbox] Windows guest crashes when on kernel 5.18
- https://www.virtualbox.org/ticket/20914
- virtualbox.org • View topic - Windows 10 Guest on Linux host dies seconds after boot
Many of the links mention Linux 5.18, but I saw instability issues with 5.15 (and others have reported issues with earlier kernel versions).
I was able to work around this issue by downgrading my linux515
and linux515-virtualbox-host-modules
packages for now. (I also downgraded virtualbox
but that might not have been necessary.)