NFS serving off NTFS panic

[Dmitri Nikulin <dnikulin@xxxxxxxxxxxxxxx>]

How to reproduce:
-Mount an NTFS partition (this was an XP-style NTFS)
-Run an NFS server that exports it
-It will crash a few seconds after nfsd is up; if not, try mounting it 
from another machine

Backtrace:

#0  dumpsys () at /usr/src/sys/kern/kern_shutdown.c:508
#1  0xc0260243 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:341
#2  0xc0260674 in panic (fmt=0xc042e18a "from debugger")
   at /usr/src/sys/kern/kern_shutdown.c:620
#3  0xc0157a19 in db_panic (addr=-1069569740, have_addr=0, count=-1,
   modif=0xdecaf654 "") at /usr/src/sys/ddb/db_command.c:450
#4  0xc01579b7 in db_command (last_cmdp=0xc04c6304, cmd_table=0xc04c6124,
   aux_cmd_tablep=0xc04bdd48, aux_cmd_tablep_end=0xc04bdd60)
   at /usr/src/sys/ddb/db_command.c:346
#5  0xc0157a83 in db_command_loop () at /usr/src/sys/ddb/db_command.c:472
#6  0xc015a0a9 in db_trap (type=3, code=0) at /usr/src/sys/ddb/db_trap.c:72
#7  0xc03fa5fe in kdb_trap (type=3, code=0, regs=0xdecaf74c)
   at /usr/src/sys/i386/i386/db_interface.c:161
#8  0xc040bd5c in trap (frame=
     {tf_fs = 24, tf_es = -557187056, tf_ds = -557187056, tf_edi = 1, 
tf_esi =               256, tf_ebp = -557123692, tf_isp = -557123720, 
tf_ebx = -1069086106, tf_edx = 0,               tf_ecx = -911559552, 
tf_eax = 18, tf_trapno = 3, tf_err = 0, tf_eip = -10695697              
40, tf_cs = 8, tf_eflags = 582, tf_esp = -1068816801, tf_ss = -1069119571})
   at /usr/src/sys/i386/i386/trap.c:743
#9  0xc03fb56b in calltrap ()
#10 0x00000018 in ?? ()
#11 0xdeca0010 in ?? ()
#12 0xdeca0010 in ?? ()
#13 0x00000001 in ?? ()
#14 0x00000100 in ?? ()
#15 0xdecaf794 in ?? ()
#16 0xdecaf778 in ?? ()
#17 0xc0470a66 in db_getdiskbyname_cmd ()
#18 0x00000000 in ?? ()
#19 0xc9aab480 in ?? ()
#20 0x00000012 in ?? ()
#21 0x00000003 in ?? ()
#22 0x00000000 in ?? ()
#23 0xc03fa934 in Debugger (msg=0xc04687ad "panic") at machine/cpufunc.h:68
#24 0xc026066b in panic (fmt=0xc0470a66 "assertion: vp == NULL in %s")
   at /usr/src/sys/kern/kern_shutdown.c:618
#25 0xc0293a3a in vop_compat_nresolve (ap=0xdecaf808)
   at /usr/src/sys/kern/vfs_default.c:244
#26 0xc02938c6 in vop_defaultop (ap=0xdecaf808)
   at /usr/src/sys/kern/vfs_default.c:155
#27 0xc02a04bc in vop_nresolve (ops=<incomplete type>, ncp=<incomplete 
type>,
   cred=0xdeb661cc) at /usr/src/sys/kern/vfs_vopops.c:1229
#28 0xc029189b in cache_resolve (ncp=0xdeb9fc60, cred=0xdeb661cc)
   at /usr/src/sys/kern/vfs_cache.c:1395
#29 0xc0295908 in nlookup (nd=0xdecafa60)
   at /usr/src/sys/kern/vfs_nlookup.c:385
#30 0xc030f517 in nfs_namei (nd=0xdecafa60, cred=0xdeb661cc, nameiop=0,
   dvpp=0x0, vpp=0xdecaf93c, fhp=0xdecafa20, len=3, slp=0xc1844c00,
   nam=0xc16241e0, mdp=0xdecaf954, dposp=0xdecaf958, dirpp=0xdecaf940,
   td=0xc9aab480, kerbflag=0, pubflag=0)
   at /usr/src/sys/vfs/nfs/nfs_subs.c:1597
#31 0xc02faf4a in nfsrv_lookup (nfsd=0xdeb66148, slp=0xc1844c00,
   td=0xc9aab480, mrq=0xdecafacc) at /usr/src/sys/vfs/nfs/nfs_serv.c:459
#32 0xc0310e9a in nfssvc_nfsd (nsd=0xdecafb34, argp=---Can't read 
userspace from dump, or kernel process---

)
   at /usr/src/sys/vfs/nfs/nfs_syscalls.c:613
#33 0xc0310791 in nfssvc (uap=0xdecafc34)
   at /usr/src/sys/vfs/nfs/nfs_syscalls.c:311
#34 0xc040c6ea in syscall2 (frame=
     {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = 0, tf_esi = 0, 
tf_ebp = -1077937312, tf_isp = -557122188, tf_ebx = 4, tf_edx = 1, 
tf_ecx = -7, tf_eax = 155, tf_trapno = 12, tf_err = 2, tf_eip = 
134518624, tf_cs = 31, tf_eflags = 663, tf_esp = -1077937740, tf_ss = 
47}) at /usr/src/sys/i386/i386/trap.c:1350
#35 0xc03fb5fa in Xint0x80_syscall ()
#36 0x0000002f in ?? ()
#37 0x0000002f in ?? ()
#38 0x0000002f in ?? ()
#39 0x00000000 in ?? ()
#40 0x00000000 in ?? ()
#41 0xbfbffb60 in ?? ()
#42 0xdecafd74 in ?? ()
#43 0x00000004 in ?? ()
#44 0x00000001 in ?? ()
#45 0xfffffff9 in ?? ()
#46 0x0000009b in ?? ()
#47 0x0000000c in ?? ()
#48 0x00000002 in ?? ()
#49 0x08049760 in ?? ()
#50 0x0000001f in ?? ()
#51 0x00000297 in ?? ()
#52 0xbfbff9b4 in ?? ()
#53 0x0000002f in ?? ()
#54 0x00000000 in ?? ()
#55 0x00000000 in ?? ()
#56 0x00000000 in ?? ()
#57 0x00000000 in ?? ()
#58 0x1c073000 in ?? ()
#59 0xff800000 in ?? ()
#60 0xc0534810 in ithread_ary ()
#61 0xdecaf3f4 in ?? ()
#62 0xdecaf3e4 in ?? ()
#63 0xc9aab480 in ?? ()
#64 0xc026467e in lwkt_preempt (ntd=---Can't read userspace from dump, 
or kernel process---

) at /usr/src/sys/kern/lwkt_thread.c:763
Previous frame inner to this frame (corrupt stack?)