Warning: Permanently added '10.128.0.18' (ECDSA) to the list of known hosts.
executing program
login: vm_object_vndeallocate 0xfffff800124fd000: tag ufs, type VREG
    usecount 2, writecount 1, refcount 2
    flags (VI_ACTIVE)
    v_object 0xfffff80012506e00 ref 0 pages 0 cleanbuf 0 dirtybuf 0
    lock type ufs: UNLOCKED
	nlink=1, effnlink=1, size=0, extsize 0
	generation=bafe7843, uid=0, gid=0, flags=0x0
	ino 197775, on dev gpt/rootfs
panic: vm_object_vndeallocate: bad object reference count
cpuid = 0
time = 1557776286
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe00212046f0
vpanic() at vpanic+0x1e0/frame 0xfffffe0021204750
panic() at panic+0x43/frame 0xfffffe00212047b0
vm_object_collapse() at vm_object_collapse/frame 0xfffffe0021204810
vn_mmap() at vn_mmap+0x2e3/frame 0xfffffe0021204890
kern_mmap() at kern_mmap+0x8a8/frame 0xfffffe0021204950
sys_mmap() at sys_mmap+0x38/frame 0xfffffe0021204980
amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe0021204ab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0021204ab0
--- syscall (0, FreeBSD ELF64, nosys), rip = 0x41c32a, rsp = 0x7fffffffead8, rbp = 0x7fffffffeb40 ---
KDB: enter: panic
[ thread pid 759 tid 100095 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why