Hard(?) lock when reassociating ath with
wpa_supplicant on RELENG_7
Alexandre "Sunny" Kovalenko
alex.kovalenko at verizon.net
Sat Jul 12 02:08:19 UTC 2008
On Fri, 2008-05-16 at 12:23 -0400, Sam Leffler wrote:
> Alexandre "Sunny" Kovalenko wrote:
> > On Mon, 2008-05-12 at 19:33 -0700, Sam Leffler wrote:
> >> Alexandre "Sunny" Kovalenko wrote:
> >>> I seem to be able to lock my machine by going into wpa_cli and asking it
> >>> to 'reassoc'. The reason for question mark after "hard" is that debug
> >>> information (caused by wlandebug and athdebug) is being printed on the
> >>> console. The only way to get machine's attention is to hold power button
> >>> for 8 seconds.
> >> So this is just livelock due to console debug msgs.
> > I am not sure, I have parsed this well enough, so I will try to clarify:
> > machine becomes unresponsive *without* any debugging turned on, to an
> > extent that pressing the power button twice *does not* generate ACPI
> > console message (something to the tune of "going into S5 already --
> > gimme a break"). If I turn ath debugging on, I do see those messages,
> > and only them, scrolling on the console.
>
> Guess I misunderstood you.
I have finally got enough time and equipment to investigate this
further. Here are some conclusions:
-- at this point (RELENG_7 as of July 9th around 15:30 EST) it is indeed
a livelock.
-- all system does, is executing ath_intr (if_ath.c) in the tight loop
with the same status -- 0x1000 AKA HAL_INT_MIB. In order to eliminate
possibility that I have caused livelock with the debug messages, I have
put conditional panic() into ath_intr, as soon as sc->sc_stats.ast_mib
reaches 10,000. Without any kind of the debug messages, it will be
triggered within 40-60 seconds after starting of wpa_supplicant.
-- I suspect that comment below, might not hold true on my equipment
if (status & HAL_INT_MIB) {
sc->sc_stats.ast_mib++;
/*
* Disable interrupts until we service the MIB
* interrupt; otherwise it will continue to fire.
*/
ath_hal_intrset(ah, 0);
/*
* Let the hal handle the event. We assume it will <============
* clear whatever condition caused the interrupt. <============
*/
ath_hal_mibevent(ah, &sc->sc_halstats);
ath_hal_intrset(ah, sc->sc_imask);
}
My hardware is:
ath_hal: 0.9.20.3 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413,
RF5413)
ath0: <Atheros 5212> mem 0xedf00000-0xedf0ffff irq 17 at device 0.0 on
pci3
ath0: [ITHREAD]
ath0: using obsoleted if_watchdog interface
ath0: Ethernet address: 00:16:cf:26:2f:3f
ath0: mac 10.3 phy 6.1 radio 10.2
My wpa_supplicant.conf is:
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
eapol_version=2
network={
ssid="XXXXXXXXXXX"
scan_ssid=1
priority=1
proto=WPA
pairwise=TKIP
group=TKIP
key_mgmt=WPA-PSK
psk="xxxxxxxxxxxxxxxxxxxxxx"
}
Access point is Netgear WNDR3300-1B with 11N and 11G SSID set up to
different values. Only 11G SSID is configured in wpa_supplicant.conf. In
the test setup, AP is with 10' (3m) from the laptop.
AP is successfully used by handful of Windows clients (including this
same laptop) and iBook G4.
Neither wpa_supplicant with '-d -d' nor wlandebug 0xFFFFFFFF show
anything but normal scan.
athdebug 0xFFFFFFFF loops with ath_intr: status 0x1000 until I power
down my laptop.
I would appreciate any suggestion on what I can investigate further --
at this point I have comfortable console setup and should be able to
field requests for further information much better.
--
Alexandre "Sunny" Kovalenko (Олександр Коваленко)
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