panic: MNT_DEFERRED requires MNT_RECURSE | MNT_FORCE
cpuid = 1
time = 520
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0xc6/frame 0xfffffe0057264610
kdb_backtrace() at kdb_backtrace+0xd0/frame 0xfffffe0057264770
vpanic() at vpanic+0x257/frame 0xfffffe0057264930
panic() at panic+0xb5/frame 0xfffffe00572649f0
dounmount() at dounmount+0x1783/frame 0xfffffe0057264b30
kern_unmount() at kern_unmount+0x648/frame 0xfffffe0057264d10
amd64_syscall() at amd64_syscall+0x4e2/frame 0xfffffe0057264f30
fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe0057264f30
--- syscall (198, FreeBSD ELF64, __syscall), rip = 0x3a817a, rsp = 0x82518bf08, rbp = 0x82518bf80 ---
KDB: enter: panic
[ thread pid 1465 tid 100873 ]
Stopped at      kdb_enter+0x6e: movq    $0,0x2587a77(%rip)
db> 
db> set $lines = 0
db> set $maxwidth = 0
db> show registers
cs                        0x20
ds                        0x3b
es                        0x3b
fs                        0x13
gs                        0x1b
ss                        0x28
rax                       0x12
rcx         0xfffffe0072e00000
rdx                    0x7ffff
rbx         0xffffffff8283c160  .str.27
rsp         0xfffffe0057264750
rbp         0xfffffe0057264770
rsi                    0x80001
rdi         0xffffffff81664139  printf+0x149
r8                           0
r9                  0xffffffff
r10                          0
r11                       0x7f
r12         0xfffffe0058ba0000
r13         0xfffffffffffffffd
r14         0xffffffff8283c160  .str.27
r15                          0
rip         0xffffffff8164d41e  kdb_enter+0x6e
rflags                    0x46
kdb_enter+0x6e: movq    $0,0x2587a77(%rip)
db>