Bug 13198

#gdb -k *28

panic messages:
---
panic: vm_fault: fault on nofault entry, addr: ce4c9000

syncing disks... panic: from debugger
(da1:ahc1:0:1:0): SYNCHRONIZE CACHE. CDB: 35 0 0 0 0 0 0 0 0 0
(da1:ahc1:0:1:0): ILLEGAL REQUEST asc:20,0
(da1:ahc1:0:1:0): Invalid command operation code

dumping to dev 20401, offset 1691306
dump 512 ...
---
#0  boot (howto=260) at ../../kern/kern_shutdown.c:285
285                     dumppcb.pcb_cr3 = rcr3();
(kgdb) where
#0  boot (howto=260) at ../../kern/kern_shutdown.c:285
#1  0xc013cf39 in panic (fmt=0xc01fb0f8 "from debugger")
    at ../../kern/kern_shutdown.c:446
#2  0xc01221dd in db_panic (addr=-1071763569, have_addr=0, count=-1,
    modif=0xd302f76c "") at ../../ddb/db_command.c:432
#3  0xc012217d in db_command (last_cmdp=0xc0213aa4, cmd_table=0xc0213904,
    aux_cmd_tablep=0xc0225818) at ../../ddb/db_command.c:332
#4  0xc0122242 in db_command_loop () at ../../ddb/db_command.c:454
#5  0xc01246bb in db_trap (type=3, code=0) at ../../ddb/db_trap.c:71
#6  0xc01e2d6a in kdb_trap (type=3, code=0, regs=0xd302f85c)
    at ../../i386/i386/db_interface.c:157
#7  0xc01ebd14 in trap (frame={tf_es = 16, tf_ds = 16, tf_edi = -1071815412,
      tf_esi = 134, tf_ebp = -754780000, tf_isp = -754780028, tf_ebx = 0,
      tf_edx = -1071600628, tf_ecx = -1072984320, tf_eax = 38, tf_trapno = 3,
      tf_err = 0, tf_eip = -1071763569, tf_cs = 8, tf_eflags = 598,
      tf_esp = -1071600644, tf_ss = -1071611704}) at ../../i386/i386/trap.c:548
#8  0xc01e2f8f in Debugger (msg=0xc02080c8 "manual escape to debugger")
    at ../../i386/i386/db_interface.c:317
#9  0xc01de778 in scgetc (kbd=0xc0246600, flags=2)
    at ../../dev/syscons/syscons.c:3726
#10 0xc01d99f8 in sckbdevent (thiskbd=0xc0246600, event=0, arg=0x0)
    at ../../dev/syscons/syscons.c:822
#11 0xc01d63d7 in atkbd_intr (kbd=0xc0246600, arg=0x0)
    at ../../dev/kbd/atkbd.c:563
#12 0xc01efc1c in atkbd_isa_intr (unit=0) at ../../i386/isa/atkbd_isa.c:84
#13 0xc01e4a7a in vec1 ()
#14 0xc0159d93 in getblk (vp=0xd2d77ec0, blkno=131184, size=8192, slpflag=0,
    slptimeo=0) at ../../kern/vfs_bio.c:1424
#15 0xc0158761 in bread (vp=0xd2d77ec0, blkno=131184, size=8192, cred=0x0,
    bpp=0xd302fa30) at ../../kern/vfs_bio.c:282
#16 0xc01bbf98 in ffs_update (vp=0xd3ddbd80, waitfor=0)
    at ../../ufs/ffs/ffs_inode.c:98
#17 0xc01c0766 in ffs_fsync (ap=0xd302fab8) at ../../ufs/ffs/ffs_vnops.c:258
#18 0xc01beb8b in ffs_sync (mp=0xc3004a00, waitfor=2, cred=0xc1138000,
    p=0xc024bb7c) at vnode_if.h:499
#19 0xc01619c3 in sync (p=0xc024bb7c, uap=0x0) at ../../kern/vfs_syscalls.c:549
#20 0xc013cae1 in boot (howto=256) at ../../kern/kern_shutdown.c:203
#21 0xc013cf39 in panic (
    fmt=0xc02067ce "vm_fault: fault on nofault entry, addr: %lx")
    at ../../kern/kern_shutdown.c:446
#22 0xc01c8b6e in vm_fault (map=0xc023e7b8, vaddr=3461124096,
    fault_type=1 '\001', fault_flags=0) at ../../vm/vm_fault.c:232
#23 0xc01ebf40 in trap_pfault (frame=0xd302fc40, usermode=0, eva=3461126819)
    at ../../i386/i386/trap.c:824
#24 0xc01ebbf2 in trap (frame={tf_es = 16, tf_ds = -1012727792,
      tf_edi = 35487, tf_esi = -1012706816, tf_ebp = -754778880,
      tf_isp = -754779032, tf_ebx = -833840481, tf_edx = -847649360,
      tf_ecx = 8191, tf_eax = 43679, tf_trapno = 12, tf_err = 0,
      tf_eip = -1071900669, tf_cs = 8, tf_eflags = 66182, tf_esp = -747118080,
      tf_ss = -754778332}) at ../../i386/i386/trap.c:437
#25 0xc01c1803 in ufs_lookup (ap=0xd302fd3c) at ../../ufs/ufs/ufs_lookup.c:238
#26 0xc01c6615 in ufs_vnoperate (ap=0xd302fd3c)
    at ../../ufs/ufs/ufs_vnops.c:2299
#27 0xc015bb48 in vfs_cache_lookup (ap=0xd302fd98) at vnode_if.h:55
#28 0xc01c6615 in ufs_vnoperate (ap=0xd302fd98)
    at ../../ufs/ufs/ufs_vnops.c:2299
#29 0xc015e01d in lookup (ndp=0xd302ff00) at vnode_if.h:31
#30 0xc015daf0 in namei (ndp=0xd302ff00) at ../../kern/vfs_lookup.c:152
#31 0xc01652bf in vn_open (ndp=0xd302ff00, fmode=1538, cmode=128)
    at ../../kern/vfs_vnops.c:88
#32 0xc016201d in open (p=0xd2f5d160, uap=0xd302ff94)
    at ../../kern/vfs_syscalls.c:935
#33 0xc01ec523 in syscall (frame={tf_es = 39, tf_ds = 39,
      tf_edi = -1077954700, tf_esi = -10777272, tf_ebp = -1077944932,
      tf_isp = -754778140, tf_ebx = 0, tf_edx = 33, tf_ecx = 0, tf_eax = 5,
      tf_trapno = 7, tf_err = 2, tf_eip = 671740392, tf_cs = 31,
      tf_eflags = 582, tf_esp = -1077963708, tf_ss = 39})
    at ../../i386/i386/trap.00
#34 0xc01e36bc in Xint0x80_syscall ()
#35 0x804db00 in ?? ()
#36 0x8049425 in ?? ()

Fix: 

Unknown.
How-To-Repeat: 
Use heavy loaded NFSv3, mntudp, - this one is server.