[PANIC] ufs_dirbad: bad dir

FreeBSD 6.0-CURRENT FreeBSD 6.0-CURRENT #486: Mon Apr 25 09:41:31 PDT 2005 

[GDB will not be able to debug user-mode threads: /usr/lib/libthread_db.so: Undefined symbol "ps_pglobal_lookup"]
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#0  doadump () at pcpu.h:165
165		__asm __volatile("movl %%fs:0,%0" : "=r" (td));
(kgdb) where
#0  doadump () at pcpu.h:165
#1  0xc04dd3b2 in boot (howto=260) at ../../../kern/kern_shutdown.c:397
#2  0xc04dd763 in panic (fmt=0xc067b7f4 "ufs_dirbad: bad dir")
    at ../../../kern/kern_shutdown.c:553
#3  0xc05d913d in ufs_dirbad (ip=0x0, offset=0, how=0x0)
    at ../../../ufs/ufs/ufs_lookup.c:598
#4  0xc05d88bd in ufs_lookup (ap=0xf123c8f4)
    at ../../../ufs/ufs/ufs_lookup.c:286
#5  0xc064b16e in VOP_CACHEDLOOKUP_APV (vop=0x0, a=0xf123c8f4)
    at vnode_if.c:153
#6  0xc053459d in vfs_cache_lookup (ap=0x0) at vnode_if.h:82
#7  0xc064b08e in VOP_LOOKUP_APV (vop=0x0, a=0xf123c998) at vnode_if.c:100
#8  0xc05390de in lookup (ndp=0xf123cbc4) at vnode_if.h:56
#9  0xc053899f in namei (ndp=0xf123cbc4) at ../../../kern/vfs_lookup.c:201
#10 0xc054c13f in vn_open_cred (ndp=0xf123cbc4, flagp=0xf123ccc4, cmode=384, 
    cred=0xc9176980, fdidx=7) at ../../../kern/vfs_vnops.c:184
#11 0xc054be83 in vn_open (ndp=0x0, flagp=0x0, cmode=0, fdidx=0)
    at ../../../kern/vfs_vnops.c:91
#12 0xc0544578 in kern_open (td=0xc8c02d80, path=0x0, pathseg=UIO_USERSPACE, 
    flags=1, mode=438) at ../../../kern/vfs_syscalls.c:972
#13 0xc0544476 in open (td=0x0, uap=0xf123cd04)
    at ../../../kern/vfs_syscalls.c:938
#14 0xc063ad22 in syscall (frame=
      {tf_fs = 59, tf_es = 59, tf_ds = 59, tf_edi = 4, tf_esi = 673883752, tf_ebp = -1077945272, tf_isp = -249311900, tf_ebx = 673801428, tf_edx = 0, tf_ecx = 0, tf_eax = 5, tf_trapno = 22, tf_err = 2, tf_eip = 673231535, tf_cs = 51, tf_eflags = 514, tf_esp = -1077945316, tf_ss = 59}) at ../../../i386/i386/trap.c:951
#15 0xc0626baf in Xint0x80_syscall () at ../../../i386/i386/exception.s:200
#16 0x0000003b in ?? ()
#17 0x0000003b in ?? ()
#18 0x0000003b in ?? ()
#19 0x00000004 in ?? ()
#20 0x282aa668 in ?? ()
#21 0xbfbfdc48 in ?? ()
#22 0xf123cd64 in ?? ()
#23 0x282964d4 in ?? ()
#24 0x00000000 in ?? ()
#25 0x00000000 in ?? ()
#26 0x00000005 in ?? ()
#27 0x00000016 in ?? ()
#28 0x00000002 in ?? ()
#29 0x2820b2af in ?? ()
#30 0x00000033 in ?? ()
#31 0x00000202 in ?? ()
#32 0xbfbfdc1c in ?? ()
#33 0x0000003b in ?? ()
#34 0x00000000 in ?? ()
#35 0x00000000 in ?? ()
#36 0x00000000 in ?? ()
#37 0x00000000 in ?? ()
#38 0x45f2a000 in ?? ()
#39 0xc6391400 in ?? ()
#40 0xc8c02d80 in ?? ()
#41 0xf123c6fc in ?? ()
#42 0xf123c6dc in ?? ()
#43 0xc2bc0600 in ?? ()
#44 0xc04f1200 in sched_switch (td=0x282aa668, newtd=0x282964d4, flags=Cannot access memory at address 0xbfbfdc58
)
    at ../../../kern/sched_4bsd.c:971
Previous frame inner to this frame (corrupt stack?)