[newbus][aac] Lock newbus not exclusively locked _at_ /usr/HEAD/src/sys/kern/subr_bus.c:3154

Hi.

As for today's HEAD I got a panic in bad newbus locking vs aac(4) interaction.

acd0: CDRW <HL-DT-STCD-RW/DVD DRIVE GCC-T10N/1.00> at ata1-master UDMA33
panic: Lock newbus not exclusively locked _at_
/usr/HEAD/src/sys/kern/subr_bus.c:3154

cpuid = 0
KDB: enter: panic
[thread pid 0 tid 100000 ]
Stopped at      kdb_enter+0x3d: movq    $0,0x69e9e0(%rip)
db> bt
Tracing pid 0 tid 100000 td 0xffffffff80c2dc00
kdb_enter() at kdb_enter+0x3d
panic() at panic+0x17b
assert_sx() at assert_sx
bus_generic_attach() at bus_generic_attach+0x57
aac_startup() at aac_startup+0xd7
run_interrupt_driven_config_hooks() at run_interrupt_driven_config_hooks+0x6c
mi_startup() at mi_startup+0x59
btext() at btext+0x2c
db> bt 6
Tracing pid 6 tid 100038 td 0xffffff000267e720
sched_switch() at sched_switch+0x180
mi_switch() at mi_switch+0x21d
sleepq_switch() at sleepq_switch+0x123
sleepq_timedwait() at sleepq_timedwait+0x4d
_sleep() at _sleep+0x341
aac_command_thread() at aac_command_thread+0xbd
fork_exit() at fork_exit+0x12a
fork_trampoline() at fork_trampoline+0xe
--- trap 0, rip = 0, rsp = 0xffffff8000147d30, rbp = 0 ---
db> show locks
exclusive sleep mutex Giant (Giant) r = 0 (0xffffffff80c305a0) locked
_at_ /usr/HEAD/src/sys/kern/kern_module.c:117

-- 
wbr,
pluknet