panic: Unregistered use of FPU in kernel

[Konstantin Belousov]

On Thu, Sep 26, 2019 at 09:45:43AM -0600, Alan Somers wrote:
> The latest VM snapshot (FreeBSD-13.0-CURRENT-amd64-20190920-r352544.qcow2)
> instapanics on boot:
> 
> panic: Unregistered use of FPU in kernel
> 
> stack trace:
> ...
> sse42_crc32c
> readsuper
> ffs_sbget
> g_label_ufs_taste_common
> g_label_taste
> g_new_provider_event
> g_run_events
> fork_exit
> ...
> 
> Has anybody touched this area recently?  I'll try to narrow down the commit
> range.

Start with disassembling the faulting instruction.  I suspect that somehow
vital compiler switches like -mno-sse got omitted in the build.