Re: setting bssid in adhoc mode

Paul B. Mahol wrote:
> On 9/26/08, John Hay <[email protected]> wrote:
>   
>> On Thu, Sep 25, 2008 at 08:59:37PM +0200, Paul B. Mahol wrote:
>>     
>>> On 9/25/08, John Hay <[email protected]> wrote:
>>>       
>>>> On Thu, Sep 25, 2008 at 04:41:30PM +0200, Paul B. Mahol wrote:
>>>>         
>>>>> On 9/22/08, John Hay <[email protected]> wrote:
>>>>>           
>>>>>> Hi
>>>>>>
>>>>>> I'm trying out the new ath/wlan stuff in current. Should one still be
>>>>>> able to set the bssid in adhoc mode? We normally lock the bssid in
>>>>>> an adhoc network because of problems that the network split and does
>>>>>> not merge, if you do not do it.
>>>>>>
>>>>>> What I have done is this:
>>>>>>
>>>>>> # ifconfig wlan0 create wlandev ath0 wlanmode adhoc
>>>>>> # ifconfig wlan0 ssid ptamesh up
>>>>>>
>>>>>> Up to here works well. It will scan and if it finds another node with
>>>>>> the
>>>>>> same ssid, it will "lock" on that channel and use the correct bssid.
>>>>>>
>>>>>> If it does not find another node with the same ssid, it will start it
>>>>>> own thing on channel 10. But it looks like one cannot set the bssid.
>>>>>>
>>>>>> # ifconfig wlan0 bssid 02:07:ca:fe:ba:be
>>>>>> ifconfig: 02:07:ca:fe:ba:be: bad value
>>>>>>             
>>>>> I had similar experience with STA mode, instead I use ap (ap is alias
>>>>> for bssid, at least it works in STA mode)
>>>>> I never bothered is this bug in manual page, ifconfig or in something
>>>>> else
>>>>> ...
>>>>>           
>>>> Ah, thanks yes, "ifconfig wlan0 ap 02:07:ca:fe:ba:be" works just fine.
>>>> Just do not try to unset it with "ifconfig wlan0 ap -". That is an
>>>> alias for "panic now" :-)
>>>>         
>>> Well, on my system it doesnt panic here.
>>> So more info to debug "your" panic is required ...
>>>       
>> I'll have to see if I can reproduce it.
>>     
>
> I managed to reproduce panic on recent CURRENT, with two cards in adhoc mode.
> rum0 (usb2) & ndis0 (personal hacked version without usb code)
>
> I typed "ifconfig wlan0 ap -"  several times.
>
>
> bt:
>
> db:0:kdb.enter.unknown>  run lockinfo
> db:1:lockinfo> show locks
> db:1:locks>  show alllocks
> Process 1471 (ifconfig) thread 0xc4028690 (100048)
> Process 477 (syslogd) thread 0xc402b8c0 (100058)
> db:1:alllocks>  show lockedvnods
> Locked vnodes
> db:0:kdb.enter.unknown>  show pcpu
> cpuid        = 1
> curthread    = 0xc4028690: pid 1471 "ifconfig"
> curpcb       = 0xe64e1d90
> fpcurthread  = none
> idlethread   = 0xc3cb1d20: pid 10 "idle: cpu1"
> APIC ID      = 1
> currentldt   = 0x50
> spin locks held:
> db:0:kdb.enter.unknown>  bt
> Tracing pid 1471 tid 100048 td 0xc4028690
> ieee80211_ht_adjust_channel(c46a8000,0,2,2,80000002,...) at
> ieee80211_ht_adjust_channel+0x30
> adhoc_pick_bss(c4053000,c4113800,c0a1ebc3,23a,c3dd0108,...) at
> adhoc_pick_bss+0x100
> ieee80211_check_scan(c4113800,2,7fffffff,0,0,...) at ieee80211_check_scan+0x20d
> ieee80211_check_scan_current(c4113800,4,c0a1fb47,6c,c4113800,...) at
> ieee80211_check_scan_current+0x45
> adhoc_newstate(c4113800,1,0,648,e64e1aa0,...) at adhoc_newstate+0x219
> ieee80211_new_state_locked(c4113800,0,c0a1e64c,49c,0,...) at
> ieee80211_new_state_locked+0xc4
> ieee80211_init(c4113800,c0a24a64,6,c41adc00,1b9,...) at ieee80211_init+0x45
> ieee80211_ioctl_set80211(c3e1ec00,801c69ea,c48c4240,c0709084,c4028690,...)
> at ieee80211_ioctl_set80211+0xe5
> in_control(c4158188,801c69ea,c48c4240,c3e1ec00,c4028690,...) at in_control+0xdc4
> ifioctl(c4158188,801c69ea,c48c4240,c4028690,801c69ea,...) at ifioctl+0x34a
> soo_ioctl(c43c9d90,801c69ea,c48c4240,c41adc00,c4028690,...) at soo_ioctl+0x397
> kern_ioctl(c4028690,3,801c69ea,c48c4240,504110,...) at kern_ioctl+0x1dd
> ioctl(c4028690,e64e1cf8,c,c06d3f58,c0702bf0,...) at ioctl+0x134
> syscall(e64e1d38) at syscall+0x283
> Xint0x80_syscall() at Xint0x80_syscall+0x20
> --- syscall (54, FreeBSD ELF32, ioctl), eip = 0x281a9a43, esp =
> 0xbfbfe48c, ebp = 0xbfbfe4d8 ---
>
> here is panic message:
>
> Fatal trap 12: page fault while in kernel mode
> cpuid = 1; apic id = 01
> fault virtual address   = 0x0
> fault code              = supervisor read, page not present
> instruction pointer     = 0x20:0xc0a0c5b0
> stack pointer           = 0x28:0xe64e1980
> frame pointer           = 0x28:0xe64e1990
> 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         = 1471 (ifconfig)
> exclusive sleep mutex ndis0_com_lock (ndis0_com_lock) r = 1
> (0xc46a8014) locked @
> /usr/src/sys/modules/wlan/../../net80211/ieee80211_scan.c:570
> exclusive sleep mutex ndis0_com_lock (ndis0_com_lock) r = 1
> (0xc46a8014) locked @
> /usr/src/sys/modules/wlan/../../net80211/ieee80211_scan.c:570
> exclusive lockmgr bufwait (bufwait) r = 0 (0xd7d083c0) locked @
> /usr/src/sys/kern/vfs_bio.c:2443
> exclusive lockmgr ufs (ufs) r = 0 (0xc41a2058) locked @
> /usr/src/sys/kern/vfs_vnops.c:593
>
> 0xc41a2000: tag ufs, type VREG
>     usecount 1, writecount 1, refcount 4 mountedhere 0
>     flags ()
>     v_object 0xc413aaa8 ref 0 pages 7
>      lock type ufs: EXCL by thread 0xc402b8c0 (pid 477)
>
>         ino 164881, on dev ad4s1d
>   
Looks like adhoc_pick_channel returned NULL which was unexpected.  Don't 
have a quick fix but it's possible no channel may be selected so the 
code is wrong.  I rarely touch adhoc mode so this stuff is lightly tested.

    Sam

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