panic: vm_object_vndeallocate: bad object reference count cpuid = 1 time = 1557809250 KDB: stack backtrace: db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0020dca6f0 vpanic() at vpanic+0x1e0/frame 0xfffffe0020dca750 panic() at panic+0x43/frame 0xfffffe0020dca7b0 vm_object_collapse() at vm_object_collapse/frame 0xfffffe0020dca810 vn_mmap() at vn_mmap+0x2e3/frame 0xfffffe0020dca890 kern_mmap() at kern_mmap+0x8a8/frame 0xfffffe0020dca950 sys_mmap() at sys_mmap+0x38/frame 0xfffffe0020dca980 amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe0020dcaab0 fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0020dcaab0 --- syscall (0, FreeBSD ELF64, nosys), rip = 0x41c31a, rsp = 0x7fffffffead8, rbp = 0x7fffffffeb40 --- KDB: enter: panic [ thread pid 759 tid 100083 ] Stopped at kdb_enter+0x6a: movq $0,kdb_why