Monitor mode not working for iwi(4) on 7.X

[Alexey Dokuchaev]

On Thu, Oct 07, 2010 at 08:43:37PM +0200, Bernhard Schmidt wrote:
> Try the attached patch, this is basically the code from stable/6
> ported to head and stable/7. I did only some basic tests but monitor
> mode seems to work and it is still possible to use the card in STA
> mode.
> 
> I'm not sure why that got lost, but there must be a reason I'm not
> seeing right now. If someone has more knowledge about that, please
> let me know, otherwise I intend to commit it this weekend.

Unfortunately, I am getting instant panic when trying any of aircrack-ng
suite utilities ("ifconfig iwi0 scan/list scan" works though):

Fatal trap 12: page fault while in kernel mode
fault virtual address   = 0x0
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0xc0768d42
stack pointer           = 0x28:0xe4112c80
frame pointer           = 0x28:0xe4112c98
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 35 (iwi0 taskq)

(kgdb) bt
...
#6  0xc060cae0 in trap_fatal (frame=0xe4112c40, eva=0)
    at /usr/src/sys/i386/i386/trap.c:941
#7  0xc060cd90 in trap_pfault (frame=0xe4112c40, usermode=0, eva=0)
    at /usr/src/sys/i386/i386/trap.c:863
#8  0xc060d7f7 in trap (frame=0xe4112c40) at /usr/src/sys/i386/i386/trap.c:541
#9  0xc05f4d9b in calltrap () at /usr/src/sys/i386/i386/exception.s:166
#10 0xc0768d42 in iwi_monitor_scan (arg=0xc3dcc000, npending=4)
    at /usr/src/sys/modules/iwi/../../dev/iwi/if_iwi.c:2744
...
(kgdb) f 10
#10 0xc0768d42 in iwi_monitor_scan (arg=0xc3dcc000, npending=4)
    at /usr/src/sys/modules/iwi/../../dev/iwi/if_iwi.c:2744
2744            struct iwi_softc *sc = ic->ic_ifp->if_softc;
(kgdb) l
2739
2740    static void
2741    iwi_monitor_scan(void *arg, int npending)
2742    {
2743            struct ieee80211com *ic = arg;
2744            struct iwi_softc *sc = ic->ic_ifp->if_softc;
2745            IWI_LOCK_DECL;
2746
2747            IWI_LOCK(sc);
2748            (void) iwi_scanchan(sc, 2000, 0);
(kgdb) p ((struct ieee80211com *)arg)->ic_ifp
$1 = (struct ifnet *) 0x0

Any suggestions?

./danfe