BUG: unable to handle kernel NULL pointer derference at virtual address 00000218
 printing eip:
c05773fe
*pde = 00000000
Oops: 0000 [#1]
PREEMPT
Modules linked in: rt2500pci rt2x00pci rt2x00lib radeon drm
CPU:    0
EIP:    0060:[<c05773fe>]    Not tainted VLI
EFLAGS: 0010286    (2.6.21-ge42d23f3 #8)
EIP is at ieee80211_ibss_add_sta+0xae/0x130
eax: f76292c0   ebx: f78c381c   ecx: 00000000   edx: 00000102
esi: f6a091a0   edi: f76292c0   ebp: f6bb8000   esp: f641dc38
ds: 007b   es: 007b   fs: 0000  gs: 0033  ss: 0068
Process ip (pid: 1621, ti=f641c000 task=f78f8c30 task.ti=f641c000)
Stack: 00000020 f782f800 00000000 00000001 000000e3 0000000f 000000ae 000000eb
       f6bb8000 f6a091a0 c193e8c0 f78c3822 f6bb83a0 00000002 f78c3812 c0569b8a
       f78c381c df82f5ea f7e90458 f7cfea10 00000001 f7cfea28 00000018 00000000
Call Trace:
 [<c0569b8a>] __ieee80211_rx+0xa5a/0xc10
 [<c0180b5a>] dentry_iput+0xda/0x120
 [<c056c34f>] ieee80211_tasklet_handler+0xaf/0xe0
 [<c02f3c9f>] _atomic_dec_and_loc+0x2f/0x50
 [<c0121c43>] tasklet_action+0x33/0x70
 [<c0121b72>] __do_softirq+0x52/0xa0
 [<c0121c05>] do_softirq+0x45/0x50
 [<c0122023>] local_bh_enable+0x53/0xa0
 [<c047f74b>] dev_mc_upload+0x3b/0x50
 [<c047d16c>] dev_open+0x5c/0x80
 [<c056d017>] ieee80211_open+0x317/0x420
 [<c0121b86>] __do_softirq+0x66/0xa0
 [<c047d149>] dev_open+0x39/0x80
 [<c047b8cc>] dev_change_flags+0x5c/0x140
 [<c04c3613>] devinet_ioctl+0x563/0x6e0
 [<c0472310>] sock_ioctl+0x0/0x1c0
 [<c04723bf>] sock_ioctl+0xaf/0x1c0
 [<c0472310>] sock_ioctl+0x0/0x1c0
 [<c017b81b>] do_ioctl+0x2b/0x90
 [<c017b8dc>] vfs_ioctl+0x5c/0x2b0
 [<c017bb6d>] sys_ioctl+0x3d/0x70
 [<c010406e>] sysenter_past_esp+0x5f/0x85
 =======================
Code: 00 00 00 c7 04 24 5c 09 6d c0 89 44 24 04 e8 fa 5f ba ff 89 d9 89 ea 89 f0 c7 04 24 20 00 00 00 e8 48 d1 ff ff 85 c0 89 c7 74 95 <a1> 18 02 00 00 8b 97 8c 00 00 00 89 f1 89 47 64 8b 87 88 00 00
EIP: [<c05773fe>] ieee_80211_ibss_add_sta+0xae/0x130 SS:ESP 0068:f641dc38
Kernel panic - not syncing: Fatal exception in interrupt