Freebsd 8.0 system freeze

[Peter Pieczora]

Hi,

I recently upgraded from 7.2-STABLE to 8.0-RELEASE, and I'm encountering 
frequent system freezes (hang ups), which end in a reboot.

There is no indication of any panic, no messages are generated and no core 
dump files (sysctl kern.coredump=1).

System runs on IBM T43 with intel wireless chipset, iwi modules are loaded 
during boot via /boot/loader.conf. 

legal.intel_iwi.license_ack=1
if_iwi_load="YES"
wlan_load="YES"
firmware_load="YES"
iwi_bss_load="YES"
iwi_ibss_load="YES"
iwi_monitor_load="YES

Typically msg. look something like that or similar (iwi0 line gets repeated 
twice or 3 times):

Dec  1 22:02:12 local kernel: wlan0: link state changed to DOWN
Dec  1 22:02:19 local kernel: wlan0: link state changed to UP
Dec  1 22:02:19 local kernel: iwi0: need multicast update callback
Dec  1 22:02:30 local kernel: wlan0: link state changed to DOWN
Dec  1 22:04:14 local syslogd: kernel boot file is /boot/kernel/kernel

Is anyone else seeing this?

ATM I am at work using bge0 interface and system runs without freezing so far. 
Could this situation be attributed to iwi driver or maybe wlandev?