ata-related panic

Hi,

I got this lovely panic when trying to upgrade from an April 15th kernel. 
This panic happened too soon in the boot process for my dumpdir to get 
set. Anyone have any clues on this one while I gather more data?

em0: link state changed to UP
unknown: WARNING - ATA_IDENTIFY requeued due to channel reset LBA=0
lock order reversal
  1st 0xc50ae6e0 ATA state lock (ATA state lock) _at_ 
/usr/src/sys/kern/kern_timeout.c:263
  2nd 0xc4f73344 user map (user map) _at_ /usr/src/sys/vm/vm_map.c:2997
KDB: stack backtrace:
kdb_backtrace(c06dbd1b,c4f73344,c06eb71c,c06eb71c,c06eb79c) at kdb_backtrace+0x2f
witness_checkorder(c4f73344,9,c06eb79c,bb5,12b) at witness_checkorder+0x6d0
_sx_xlock(c4f73344,c06eb79c,bb5,bd5,e900cac8) at _sx_xlock+0x7f
_vm_map_lock_read(c4f73300,c06eb79c,bb5,100018a,deadc000) at _vm_map_lock_read+0x4a
vm_map_lookup(e900cb60,deadc000,1,e900cb64,e900cb54) at vm_map_lookup+0x2e
vm_fault(c1059000,deadc000,1,0,c5015d80) at vm_fault+0x7f
trap_pfault(e900cc2c,0,deadc126,e900cc0c,deadc126) at trap_pfault+0x166
trap(c0550008,c0780028,28,c5365d48,c5365d48) at trap+0x350
calltrap() at calltrap+0x5
--- trap 0xc, eip = 0xc0541af4, esp = 0xe900cc6c, ebp = 0xe900cc6c ---
device_get_softc(deadc0de,107,1,c50ae6e0,c50ae6e0) at device_get_softc+0x6
ata_timeout(c5365d48,0,c06d90a7,107,c046cb91) at ata_timeout+0x1d
softclock(0,0,c06d585c,256,c0735d60) at softclock+0x242
ithread_loop(c5019400,e900cd38,c06d5647,30d,c5019400) at ithread_loop+0x159
fork_exit(c0513923,c5019400,e900cd38) at fork_exit+0xc2
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xe900cd6c, ebp = 0 ---


Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0xdeadc126
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0xc0541af4
stack pointer           = 0x28:0xe900cc6c
frame pointer           = 0x28:0xe900cc6c
code segment            = base 0x0, limit 0xfffff, type 0x1b
                         = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 85 (swi4: clock sio)
[thread pid 85 tid 100076 ]
Stopped at      device_get_softc+0x6:   movl    0x48(%eax),%eax
db> show locks
exclusive sleep mutex ATA state lock r = 0 (0xc50ae6e0) locked _at_ /usr/src/sys/kern/kern_timeout.c:263

The kernel is:
FreeBSD 6.0-CURRENT #0: Thu May  5 02:58:38 EDT 2005    andy_at_bling.properkernel.com:/usr/obj/usr/src/sys/BLING

More information about the system can be found at:
http://bling.properkernel.com/freebsd/

Cheers,
Andy

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