panic: Data modified on freelist: word 4 of object 0xffff800000e09600 size 0x200 previous type free (0x6563 != 0xdeafbead)

Starting stack trace...
panic(ffffffff8276969b) at panic+0x159 sys/kern/subr_prf.c:229
malloc(200,2,1) at malloc+0xa85 sys/kern/kern_malloc.c:362
spkropen(1b00,8001,2000,ffff800021704b10) at spkropen+0xc0 sys/dev/isa/spkr.c:414
spec_open(ffff80002172e7b8) at spec_open+0x3e3 sys/kern/spec_vnops.c:150
VOP_OPEN(fffffd806eda5718,8001,fffffd807f7d76e8,ffff800021704b10) at VOP_OPEN+0x70 sys/kern/vfs_vops.c:138
vn_open(ffff80002172ea08,8001,0) at vn_open+0x452 sys/kern/vfs_vnops.c:177
doopenat(ffff800021704b10,ffffff9c,20002e00,8000,0,ffff80002172ebe0) at doopenat+0x26e sys/kern/vfs_syscalls.c:1126
syscall(ffff80002172ec60) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x4ad2af419a0, count: 248
End of stack trace.
syncing disks...11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11  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 db0dc653-7a57-7afa-fd77-d87c02d918a4
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 0x000f2850: 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 3.56
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