panic: trap type 4, code=0, pc=ffffffff81ee3630
Starting stack trace...
panic(ffffffff82394d6f) at panic+0x14c sys/kern/subr_prf.c:218
kerntrap(ffff80001d9337b0) at kerntrap+0x1b7 sys/arch/amd64/amd64/trap.c:316
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
pfi_ifhead_RB_REMOVE(ffffffff8284feb0,ffff800000b56900) at pfi_ifhead_RB_REMOVE+0x50 sys/net/pf_if.c:80
pfi_detach_ifgroup(ffff800000b5aa00) at pfi_detach_ifgroup+0x11b pfi_kif_unref sys/net/pf_if.c:211 [inline]
pfi_detach_ifgroup(ffff800000b5aa00) at pfi_detach_ifgroup+0x11b sys/net/pf_if.c:304
if_delgroup(ffff800000b41000,ffff800000b5aa00) at if_delgroup+0x193 sys/net/if.c:2679
if_detach(ffff800000b41000) at if_detach+0x1ab sys/net/if.c:1042
tun_clone_destroy(ffff800000b41000) at tun_clone_destroy+0x1c7 sys/net/if_tun.c:325
if_clone_destroy(ffff80001d933a60) at if_clone_destroy+0x136 sys/net/if.c:1201
tun_dev_close(5d01,7) at tun_dev_close+0x140 sys/net/if_tun.c:476
spec_close(ffff80001d933b30) at spec_close+0x311 sys/kern/spec_vnops.c:560
VOP_CLOSE(fffffd805d7b2a90,7,fffffd806c3b7ae0,ffff8000ffff8cd8) at VOP_CLOSE+0xe2 sys/kern/vfs_vops.c:177
vn_closefile(fffffd805d7f9a58,ffff8000ffff8cd8) at vn_closefile+0xd2 vn_close sys/kern/vfs_vnops.c:298 [inline]
vn_closefile(fffffd805d7f9a58,ffff8000ffff8cd8) at vn_closefile+0xd2 sys/kern/vfs_vnops.c:614
fdrop(fffffd805d7f9a58,ffff8000ffff8cd8) at fdrop+0xc2 sys/kern/kern_descrip.c:1279
closef(fffffd805d7f9a58,ffff8000ffff8cd8) at closef+0x117 sys/kern/kern_descrip.c:1263
fdfree(ffff8000ffff8cd8) at fdfree+0xf3 sys/kern/kern_descrip.c:1195
exit1(ffff8000ffff8cd8,0,0,1) at exit1+0x320 sys/kern/kern_exit.c:197
sys_exit(ffff8000ffff8cd8,ffff80001d933dc0,ffff80001d933e10) at sys_exit+0x16 sys/kern/kern_exit.c:95
syscall(ffff80001d933e90) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffee3d0, count: 237
End of stack trace.
syncing disks...9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9  giving up

dump to dev 4,1 not possible
rebooting...
SeaBIOS (version 1.8.2-google)
Total RAM Size = 0x000000006cc00000 = 1740 MiB
CPUs found: 1     Max CPUs supported: 1
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=2097152 = 1024 MiB
drive 0x000f2350: PCHS=0/0/0 translation=lba LCHS=1024/32/63 s=2097152
Sending Seabios boot VM event.
Booting from Hard Disk 0...
>> OpenBSD/amd64 BOOT 3.52
boot> show all locks
boot: illegal argument all
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