panic: vputonfreelist: lock count is not zero
Starting stack trace...
panic(ffffffff8286a871) at panic+0x159 sys/kern/subr_prf.c:229
vputonfreelist(fffffd806e0b1380) at vputonfreelist+0x1a3 sys/kern/vfs_subr.c:719
vput(fffffd806e0b1380) at vput+0xf1 sys/kern/vfs_subr.c:781
ufs_mknod(ffff80002a69bbb0) at ufs_mknod+0xf1 sys/ufs/ufs/ufs_vnops.c:186
VOP_MKNOD(fffffd80654f1998,ffff80002a69bd10,ffff80002a69bd40,ffff80002a69bc40) at VOP_MKNOD+0xc3 sys/kern/vfs_vops.c:121
domknodat(ffff80002a6c2d60,ffffff9c,20000040,2000,412dff) at domknodat+0x322 sys/kern/vfs_syscalls.c:1627
syscall(ffff80002a69bed0) at syscall+0x538 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x33aa3ce7980, count: 249
End of stack trace.
syncing disks...18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18  giving up

dump to dev 4,1 not possible
rebooting...
SeaBIOS (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 e4c28bce-9379-8bb2-f2c8-a7cf484f58e0
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 0x000f27f0: 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 3.65
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