Another VFS Related Panic.

[Kyle Butt]

This one is somehow related to one of the vop_lookup calls not zeroing
out vp on ENOENT. It might be msdos again, I was only using ufs and
msdos at the time.
I haven't been able to repeat it, I was doing quite a few things all
at the same time.

I have the core files if you need them.

Here is the back trace:

#0  dumpsys () at /usr/src/sys/kern/kern_shutdown.c:508
#1  0xc026139f in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:341
#2  0xc0261809 in panic (fmt=0xc04762e6 "assertion: vp == NULL in %s")
    at /usr/src/sys/kern/kern_shutdown.c:620
#3  0xc029605a in vop_compat_nresolve (ap=0xd7700a64)
    at /usr/src/sys/kern/vfs_default.c:244
#4  0xc0295ee2 in vop_defaultop (ap=0xd7700a64)
    at /usr/src/sys/kern/vfs_default.c:155
#5  0xc02a25c3 in vop_nresolve (ops=<incomplete type>, ncp=<incomplete type>, 
    cred=0xd6eb1688) at /usr/src/sys/kern/vfs_vopops.c:1213
#6  0xc0293e6f in cache_resolve (ncp=0xc8143f70, cred=0xd6eb1688)
    at /usr/src/sys/kern/vfs_cache.c:1395
#7  0xc0298044 in nlookup (nd=0xd7700bd8)
    at /usr/src/sys/kern/vfs_nlookup.c:385
#8  0xc02a0a15 in vn_open (nd=0xd7700bd8, fp=0xc16c4c40, fmode=1, cmode=420)
    at /usr/src/sys/kern/vfs_vnops.c:159
#9  0xc029d7a1 in kern_open (nd=0xd7700bd8, oflags=0, mode=438, 
    res=0xd7700c60) at /usr/src/sys/kern/vfs_syscalls.c:1109
#10 0xc029da22 in open (uap=0xd7700c34)
    at /usr/src/sys/kern/vfs_syscalls.c:1236
#11 0xc0411572 in syscall2 (frame=
      {tf_fs = 47, tf_es = 47, tf_ds = 47, tf_edi = 4, tf_esi =
672157792, tf_ebp = -1077942272, tf_isp = -680522380, tf_ebx =
672081848, tf_edx = 672157792, tf_ecx = 16, tf_eax = 5, tf_trapno =
12, tf_err = 2, tf_eip = 672004148, tf_cs = 31, tf_eflags = 663,
tf_esp = -1077942316, tf_ss = 47})
    at /usr/src/sys/i386/i386/trap.c:1350
#12 0xc03fc85a in Xint0x80_syscall ()
#13 0x0000002f in ?? ()
#14 0x0000002f in ?? ()
#15 0x0000002f in ?? ()
#16 0x00000004 in ?? ()
#17 0x28105060 in ?? ()
#18 0xbfbfe800 in ?? ()
#19 0xd7700d74 in ?? ()
#20 0x280f27b8 in ?? ()
#21 0x28105060 in ?? ()
#22 0x00000010 in ?? ()
#23 0x00000005 in ?? ()
#24 0x0000000c in ?? ()
#25 0x00000002 in ?? ()
#26 0x280df834 in ?? ()
#27 0x0000001f in ?? ()
#28 0x00000297 in ?? ()
#29 0xbfbfe7d4 in ?? ()
#30 0x0000002f in ?? ()
#31 0x00000000 in ?? ()
#32 0x00000000 in ?? ()
#33 0x00000000 in ?? ()
#34 0x00000000 in ?? ()
#35 0x01ed1000 in ?? ()
#36 0x00000001 in ?? ()
#37 0xc0544b10 in ithread_ary ()
#38 0xd77008b4 in ?? ()
#39 0xd77008a0 in ?? ()
#40 0xc9ace060 in ?? ()
#41 0xc0265eb2 in lwkt_preempt (ntd=---Can't read userspace from dump,
or kernel process---

) at /usr/src/sys/kern/lwkt_thread.c:763