uvm_fault(0xfffffd807effb000, 0x8, 0, 1) -> e
fatal page fault in supervisor mode
trap type 6 code 0 rip ffffffff81c58c7e cs 8 rflags 10246 cr2 8 cpl 0 rsp ffff8000293918c0
gsbase 0xffffffff82bebff0  kgsbase 0x0
panic: trap type 6, code=0, pc=ffffffff81c58c7e
Starting stack trace...
panic(ffffffff827419cc) at panic+0x16b sys/kern/subr_prf.c:229
kerntrap(ffff800029391810) at kerntrap+0x1c7 sys/arch/amd64/amd64/trap.c:327
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
fifo_write(ffff800029391910) at fifo_write+0x4e sys/miscfs/fifofs/fifo_vnops.c:271
VOP_WRITE(fffffd8059800048,ffff8000293919c8,3,fffffd807f7d7548) at VOP_WRITE+0xbf sys/kern/vfs_vops.c:245
ktrwriteraw(ffff80002938b160,fffffd8059800048,fffffd807f7d7548,ffff800029391aa8,ffff800029391a70) at ktrwriteraw+0x15f sys/kern/kern_ktrace.c:660
ktrsysret(ffff80002938b160,89,0,ffff800029391ba0) at ktrsysret+0x18c ktrwrite2 sys/kern/kern_ktrace.c:625 [inline]
ktrsysret(ffff80002938b160,89,0,ffff800029391ba0) at ktrsysret+0x18c sys/kern/kern_ktrace.c:207
syscall(ffff800029391c20) at syscall+0x5d0 mi_syscall_return sys/sys/syscall_mi.h:131 [inline]
syscall(ffff800029391c20) at syscall+0x5d0 sys/arch/amd64/amd64/trap.c:620
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7fffffb7c0, count: 248
End of stack trace.

dump to dev 4,1 not possible
praenbioco: tkinegr..n.el
 diagnostic asseSeaBIOS (version 1.8.2-google)
Total RAM Size = 0x0000000080000000 = 2048 MiB
CPUs found: 2     Max CPUs supported: 2
SeaBIOS (version 1.8.2-google)
Machine UUID facdd91b-51c3-88c8-dda6-9406d7e40e23
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f2480: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Sending Seabios boot VM event.
Booting from Hard Disk 0...
>> OpenBSD/amd64 BOOT 3.55
boot> set $lines = 0
set: syntax error
boot> set $maxwidth = 0
set: syntax error
boot> show panic
boot: illegal argument panic
boot> trace
boot> show registers
boot> show proc
boot> ps
boot> show all locks
boot> show malloc
boot> show all pools
boot> machine ddbcpu 0
machine: syntax error
boot> trace
boot> machine ddbcpu 1
machine: syntax error
boot> trace