Hard lockup CURRENT lockup with ath0 and no wireless networks in proximity

Hi all

I have more or less recent 8-CURRENT.

And I've noticed that attempt to start wireless (start of
wpa_supplicatnt) when there is no wireless networks in proximity leads
to hard lockup of notebook, even DDB can't be called.

I have IBM T60 with:
FreeBSD 8.0-CURRENT #3: Tue Jul 15 14:42:12 MSD 2008
    root_at_vbook:/usr/obj/usr/src/sys/VBOOK

ath_hal: 0.9.20.3 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413,
RF5413)
ath0: <Atheros 5212> mem 0xedf00000-0xedf0ffff irq 17 at device 0.0 on
pci3
ath0: [ITHREAD]
ath0: WARNING: using obsoleted if_watchdog interface
ath0: mac 10.3 phy 6.1 radio 10.2
wlan0: Ethernet address: 00:19:7d:44:44:44

Once I've noticed extremely high interrupt rate before lockup.

In case when there is wireless networks around everything goes as
expected.

Any hints will be very appreciated.

-- 
Vladimir B. Grebenschikov
vova_at_fbsd.ru