Reader / writer lock error: rw_vector_exit: assertion failed: RW_COUNT(rw) != 0

[Sarton O'Brien <bsd-xen%roguewrt.org@localhost>]

On an NFS server, I moved a directory within a mount currently being accessed 
by a client.

No error occurred until I issued pwd on the client that was within the 
non-existent directory:

panic: lock error
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip ffffffff80364ab5 cs e030 rflags 246 cr2  7f7ffda11ed0 
cpl 0 rsp ffffa0002535f7e0
Stopped in pid 4734.1 (ksh) at  netbsd:breakpoint+0x5:  leave
breakpoint() at netbsd:breakpoint+0x5
panic() at netbsd:panic+0x255
lockdebug_abort() at netbsd:lockdebug_abort+0x42
rw_vector_exit() at netbsd:rw_vector_exit+0xa6
vlockmgr() at netbsd:vlockmgr+0xd8
VOP_UNLOCK() at netbsd:VOP_UNLOCK+0x28
vput() at netbsd:vput+0x1d
getcwd_common() at netbsd:getcwd_common+0x30f
sys___getcwd() at netbsd:sys___getcwd+0xc3
syscall() at netbsd:syscall+0x98
ds          0xf7f0
es          0xe02b
fs          0xf7a0
gs          0x207
rdi         0
rsi         0xd
rbp         0xffffa0002535f7e0
rbx         0xffffa0002535f7f0
rdx         0
rcx         0
rax         0x1
r8          0xffffffff80577f80  cpu_info_primary
r9          0x1
r10         0xffffa0002535f700
r11         0xffffffff8037c460  xenconscn_putc
r12         0x100
r13         0xffffffff803ed4e1  copyright+0xd281
r14         0xffffffff80574000  rwlock_lockops
r15         0xffffa00001403400
rip         0xffffffff80364ab5  breakpoint+0x5
cs          0xe030
rflags      0x246
rsp         0xffffa0002535f7e0
ss          0xe02b
netbsd:breakpoint+0x5:  leave

Sarton