panic: trap type 4, code=0, pc=ffffffff818a9550
Starting stack trace...
panic(ffffffff823914b9) at panic+0x14c sys/kern/subr_prf.c:218
kerntrap(ffff80001d942df0) at kerntrap+0x1b7 sys/arch/amd64/amd64/trap.c:316
alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b
pfi_ifhead_RB_REMOVE(ffffffff828057a0,ffff800000c84a00) at pfi_ifhead_RB_REMOVE+0x50 sys/net/pf_if.c:80
pfi_detach_ifgroup(ffff800000b99e80) at pfi_detach_ifgroup+0x11b pfi_kif_unref sys/net/pf_if.c:211 [inline]
pfi_detach_ifgroup(ffff800000b99e80) at pfi_detach_ifgroup+0x11b sys/net/pf_if.c:304
if_delgroup(ffff800000c86800,ffff800000b99e80) at if_delgroup+0x193 sys/net/if.c:2679
if_detach(ffff800000c86800) at if_detach+0x1ab sys/net/if.c:1042
tun_clone_destroy(ffff800000c86800) at tun_clone_destroy+0x1c7 sys/net/if_tun.c:325
if_clone_destroy(ffff80001d9430a0) 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(ffff80001d943170) at spec_close+0x311 sys/kern/spec_vnops.c:560
VOP_CLOSE(fffffd805dd17c30,7,fffffd806c3b7960,ffff80001e9c34a0) at VOP_CLOSE+0xe2 sys/kern/vfs_vops.c:177
vn_closefile(fffffd805d7f6e90,ffff80001e9c34a0) at vn_closefile+0xd2 vn_close sys/kern/vfs_vnops.c:298 [inline]
vn_closefile(fffffd805d7f6e90,ffff80001e9c34a0) at vn_closefile+0xd2 sys/kern/vfs_vnops.c:614
fdrop(fffffd805d7f6e90,ffff80001e9c34a0) at fdrop+0xc2 sys/kern/kern_descrip.c:1279
closef(fffffd805d7f6e90,ffff80001e9c34a0) at closef+0x117 sys/kern/kern_descrip.c:1263
fdfree(ffff80001e9c34a0) at fdfree+0xf3 sys/kern/kern_descrip.c:1195
exit1(ffff80001e9c34a0,0,19,1) at exit1+0x330 sys/kern/kern_exit.c:197
postsig(ffff80001e9c34a0,19) at postsig+0x560 sigexit sys/kern/kern_sig.c:1494 [inline]
postsig(ffff80001e9c34a0,19) at postsig+0x560 sys/kern/kern_sig.c:1423
userret(ffff80001e9c34a0) at userret+0x149 sys/kern/kern_sig.c:1914
syscall(ffff80001d9435f0) at syscall+0x429 mi_syscall_return sys/sys/syscall_mi.h:129 [inline]
syscall(ffff80001d9435f0) at syscall+0x429 sys/arch/amd64/amd64/trap.c:612
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffde200, count: 236
End of stack trace.
syncing disks...10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10  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 malloc
boot: illegal argument malloc
boot> show all pools
boot> machine ddbcpu 0
machine: syntax error
boot> trace
boot> machine ddbcpu 1
machine: syntax error
boot> trace