Re: v2.6.21.4-rt11

["Miguel Botón" <mboton@gmail.com>]

On Sunday 10 June 2007 15:17, Ingo Molnar wrote:
> -rt11 is a bit more experimental than usual: it includes the CFS 
> scheduler.

Great! Finally CFS is included ;)

Right now I'm using a patched kernel (2.6.21.4) with realtime-preemption patch 
and it works fine but I noticed something that I think you should know.

There's a problem with mac80211. I'm using "mac80211-8.0.1" 
and "iwlwifi-0.0.25" driver with my "Intel Pro Wireless 3945ABG" card.
When loading the "iwl3945" module or when an application (like wpa_supplicant, 
dhcpcd...) tries to do something with the card, I get this message in dmesg:

BUG: using smp_processor_id() in preemptible [00000000] code: 
wpa_supplicant/11659
caller is ieee80211_set_multicast_list+0x40/0x163 [mac80211]
 [<c0213b1d>] debug_smp_processor_id+0xad/0xb0
 [<f8e860bc>] ieee80211_set_multicast_list+0x40/0x163 [mac80211]
 [<c02e8532>] __dev_mc_upload+0x22/0x23
 [<c02e8686>] dev_mc_upload+0x24/0x37
 [<c02e52f5>] dev_change_flags+0x26/0xf6
 [<c031fc5e>] devinet_ioctl+0x539/0x6aa
 [<c02db972>] sock_ioctl+0xa2/0x1d5
 [<c02db8d0>] sock_ioctl+0x0/0x1d5
 [<c018500f>] do_ioctl+0x1f/0x6d
 [<c01850ad>] vfs_ioctl+0x50/0x273
 [<c0185304>] sys_ioctl+0x34/0x50
 [<c01040c6>] sysenter_past_esp+0x5f/0x85
 [<c0340000>] pfkey_add+0x7c7/0x8d9
 =======================
---------------------------
| preempt count: 00000001 ]
| 1-level deep critical section nesting:
----------------------------------------
.. [<c0213ac4>] .... debug_smp_processor_id+0x54/0xb0
.....[<00000000>] ..   ( <= _stext+0x3fefed0c/0xc)

Anyway, the wifi card works fine.

I got rid of this message by commenting the code of the 
function "ieee80211_set_multicast_list()" that's 
on "net/mac80211/ieee80211.c" but this isn't a proper fix.

I think you should know about this because kernel 2.6.22 already includes 
mac80211.

Greetings.

-- 
Miguel Botón