panic: Assertion tib != NULL failed at /usr/src/sys/kern/tty_inq.c:459

Hi Ed,
    Ran into this panic with the machine idle for a day or so. There's
some funky pointer problem going on based on the iostat output.
    The big difference in my kernel is the ffs code change that kib
provided a couple of days ago, but apart from that the kernel is
basically stock.
Thanks,
-Garrett

# uname -a
FreeBSD fallout.local 9.0-CURRENT FreeBSD 9.0-CURRENT #0 r221219M: Thu
May  5 12:09:37 PDT 2011
root_at_fallout.local:/usr/obj/usr/src/sys/FALLOUT  amd64

Unread portion of the kernel message buffer:
panic: Assertion tib != NULL failed at /usr/src/sys/kern/tty_inq.c:459
cpuid = 4
KDB: enter: panic
Dumping 1341 out of 12269 MB:..2%..11%..21%..32%..41%..51%..61%..71%..82%..91%

Reading symbols from /boot/kernel/linux.ko...Reading symbols from
/boot/FALLOUT.r221219/linux.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/linux.ko
Reading symbols from /boot/kernel/if_re.ko...Reading symbols from
/boot/FALLOUT.r221219/if_re.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/if_re.ko
Reading symbols from /boot/kernel/aio.ko...Reading symbols from
/boot/FALLOUT.r221219/aio.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/aio.ko
Reading symbols from /boot/kernel/nfsd.ko...Reading symbols from
/boot/FALLOUT.r221219/nfsd.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/nfsd.ko
Reading symbols from /boot/kernel/nfscommon.ko...Reading symbols from
/boot/FALLOUT.r221219/nfscommon.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/nfscommon.ko
Reading symbols from /boot/kernel/nfssvc.ko...Reading symbols from
/boot/FALLOUT.r221219/nfssvc.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/nfssvc.ko
Reading symbols from /boot/kernel/krpc.ko...Reading symbols from
/boot/FALLOUT.r221219/krpc.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/krpc.ko
Reading symbols from /boot/kernel/nfslock.ko...Reading symbols from
/boot/FALLOUT.r221219/nfslock.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/nfslock.ko
Reading symbols from /boot/kernel/nfslockd.ko...Reading symbols from
/boot/FALLOUT.r221219/nfslockd.ko.symbols...done.
done.
Loaded symbols for /boot/kernel/nfslockd.ko
#0  doadump () at pcpu.h:224
224     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) #0  doadump () at pcpu.h:224
#1  0xffffffff802a9e2c in db_fncall (dummy1=Variable "dummy1" is not available.
)
    at /usr/src/sys/ddb/db_command.c:548
#2  0xffffffff802aa161 in db_command (last_cmdp=0xffffffff808b67c0,
cmd_table=Variable "cmd_table" is not available.

) at /usr/src/sys/ddb/db_command.c:445
#3  0xffffffff802aa3a9 in db_command_loop ()
    at /usr/src/sys/ddb/db_command.c:498
#4  0xffffffff802ac337 in db_trap (type=Variable "type" is not available.
) at /usr/src/sys/ddb/db_main.c:229
#5  0xffffffff803f2948 in kdb_trap (type=3, code=0, tf=0xffffff80000f27e0)
    at /usr/src/sys/kern/subr_kdb.c:533
#6  0xffffffff8055d375 in trap (frame=0xffffff80000f27e0)
    at /usr/src/sys/amd64/amd64/trap.c:590
#7  0xffffffff805484c3 in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:228
#8  0xffffffff803f27af in kdb_enter (why=0xffffffff805daeaf "panic",
    msg=0xa <Address 0xa out of bounds>) at cpufunc.h:63
#9  0xffffffff803bf76f in panic (fmt=Variable "fmt" is not available.
)
    at /usr/src/sys/kern/kern_shutdown.c:584
#10 0xffffffff80417673 in ttyinq_line_iterate (ti=Variable "ti" is not
available.
)
    at /usr/src/sys/kern/tty_inq.c:459
#11 0xffffffff8041ac4a in ttydisc_rint (tp=0xfffffe00086a6c00, c=18 '\022',
    flags=Variable "flags" is not available.
) at /usr/src/sys/kern/tty_ttydisc.c:987
#12 0xffffffff8030ee18 in sckbdevent (thiskbd=0xfffffe0002b86a00,
event=Variable "event" is not available.
)
    at /usr/src/sys/dev/syscons/syscons.c:744
#13 0xffffffff802e1711 in kbdmux_intr (kbd=0xfffffe0002b86a00,
arg=Variable "arg" is not available.
)
    at /usr/src/sys/dev/kbdmux/kbdmux.c:549
#14 0xffffffff802e1c76 in kbdmux_kbd_intr (xkbd=Variable "xkbd" is not
available.
)
    at /usr/src/sys/dev/kbdmux/kbdmux.c:208
#15 0xffffffff803fedac in taskqueue_run_locked (queue=0xfffffe0002c25380)
    at /usr/src/sys/kern/subr_taskqueue.c:306
#16 0xffffffff803feee9 in taskqueue_run (queue=0xfffffe0002c25380)
    at /usr/src/sys/kern/subr_taskqueue.c:320
#17 0xffffffff80398bd6 in intr_event_execute_handlers (p=Variable "p"
is not available.
)
    at /usr/src/sys/kern/kern_intr.c:1257
#18 0xffffffff803999b7 in ithread_loop (arg=0xfffffe0002b58300)
    at /usr/src/sys/kern/kern_intr.c:1270
#19 0xffffffff80396252 in fork_exit (
    callout=0xffffffff80399908 <ithread_loop>, arg=0xfffffe0002b58300,
    frame=0xffffff80000f2c50) at /usr/src/sys/kern/kern_fork.c:920
#20 0xffffffff805489ee in fork_trampoline ()
    at /usr/src/sys/amd64/amd64/exception.S:603
#21 0x0000000000000000 in ?? ()
#22 0x0000000000000000 in ?? ()
#23 0x0000000000000001 in ?? ()
#24 0x0000000000000000 in ?? ()
#25 0x0000000000000000 in ?? ()
#26 0x0000000000000000 in ?? ()
#27 0x0000000000000000 in ?? ()
#28 0x0000000000000000 in ?? ()
#29 0x0000000000000000 in ?? ()
#30 0x0000000000000000 in ?? ()
#31 0x0000000000000000 in ?? ()
#32 0x0000000000000000 in ?? ()
#33 0x0000000000000000 in ?? ()
#34 0x0000000000000000 in ?? ()
#35 0x0000000000000000 in ?? ()
#36 0x0000000000000000 in ?? ()
#37 0x0000000000000000 in ?? ()
#38 0x0000000000000000 in ?? ()
#39 0x0000000000000000 in ?? ()
#40 0x0000000000000000 in ?? ()
#41 0x0000000000000000 in ?? ()
#42 0x0000000000000000 in ?? ()
#43 0x0000000000000000 in ?? ()
#44 0x0000000000000000 in ?? ()
#45 0xfffffe0002c29ce8 in ?? ()
#46 0x0000000000000000 in ?? ()
#47 0x0000000000000000 in ?? ()
#48 0xfffffe0002b6a460 in ?? ()
#49 0xffffff80000f2b40 in ?? ()
#50 0xffffff80000f2ae8 in ?? ()
#51 0xfffffe0002c298c0 in ?? ()
#52 0xffffffff803e6e6d in sched_switch (td=0xfffffe0002b58300,
    newtd=0xffffffff80399908, flags=Variable "flags" is not available.
) at /usr/src/sys/kern/sched_ule.c:1848
Previous frame inner to this frame (corrupt stack?)
(kgdb)

...

iostat

iostat: kvm_read(_tk_nin): invalid address (0x0)
iostat: disabling TTY statistics