ath9k panic when connecting to 802.11n-enabled AP

ath9k panic when connecting to 802.11n-enabled AP

[Vladimir Senkov]

Hi,

I'm new here so I apologize ahead of time if this is a known issue. In
my defense, I did a quick search on the archives.

My client machine (running wireless-testing kernel updated with git
today) panics when connecting to a hostapd access point (also running
ath9k) only when 802.11n is enabled on the access point.
More specifically, here is the hostapd configuration that causes the
client to crash:
ieee80211n=0
ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40]

If I disable 802.11n on the access point everything works ok.
Interesting enough, access point machine never crashes. At one point
both access point and client machine ran identical code and client
would always crash while the access point box would stay up. So
upgraded client to the latest and greatest and tried a few versions in
between, this panic has been very consistent. It always panics right
after 1st attempt to associate.

I was able to narrow down the panic to this assert ath_rc_ratefind_ht() in rc.c:
        ASSERT((rate_table->info[rate].valid && !ath_rc_priv->single_stream) ||
               (rate_table->info[rate].valid_single_stream &&
                ath_rc_priv->single_stream));
When I ifdef'ed this assert panic went away and everything sort of
worked (haven't tested it heavily), but the performance dropped to
about 700Kbps. I usually get 10x when 802.11n is off and there is no
panic.

Has anyone else seen this?
I'm not including panic printk's because several routines get inlined
so panic printout points to the ath_get_rate(), but if you disass that
at the right offset you'll see the trap instruction and I'm pretty
sure I am barking up the right assert here :)

Here is the lspci output:
0c:00.0 Network controller [0280]: Atheros Communications, Inc.
Unknown device [168c:002a] (rev 01)

This client is a dell E1705 laptop with mini-pcie.

-- 
Regards,
Vladimir

ath9k panic when connecting to 802.11n-enabled AP

[Sujith]

Vladimir Senkov wrote:
> My client machine (running wireless-testing kernel updated with git
> today) panics when connecting to a hostapd access point (also running
> ath9k) only when 802.11n is enabled on the access point.
> More specifically, here is the hostapd configuration that causes the
> client to crash:
> ieee80211n=0
> ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40]

ieee80211n should be 1 to enable 11n.

> If I disable 802.11n on the access point everything works ok.
> Interesting enough, access point machine never crashes. At one point
> both access point and client machine ran identical code and client
> would always crash while the access point box would stay up. So
> upgraded client to the latest and greatest and tried a few versions in
> between, this panic has been very consistent. It always panics right
> after 1st attempt to associate.
> 
> I was able to narrow down the panic to this assert ath_rc_ratefind_ht() in rc.c:
>         ASSERT((rate_table->info[rate].valid && !ath_rc_priv->single_stream) ||
>                (rate_table->info[rate].valid_single_stream &&
>                 ath_rc_priv->single_stream));
> When I ifdef'ed this assert panic went away and everything sort of
> worked (haven't tested it heavily), but the performance dropped to
> about 700Kbps. I usually get 10x when 802.11n is off and there is no
> panic.
> 
> Has anyone else seen this?

A couple of bugs were fixed dealing with this issue, but looks like more
lurk around. Can you attach the hostapd.conf, hostapd logs (hostapd -d),
client side kernel logs [1] ?, from loading the driver to the point when you associate
and get the panic.

[1]: See http://wireless.kernel.org/en/users/Drivers/ath9k on how to enable debug.

Sujith

ath9k panic when connecting to 802.11n-enabled AP

[Sujith]

Sujith wrote:
> Vladimir Senkov wrote:
> > My client machine (running wireless-testing kernel updated with git
> > today) panics when connecting to a hostapd access point (also running
> > ath9k) only when 802.11n is enabled on the access point.
> > More specifically, here is the hostapd configuration that causes the
> > client to crash:
> > ieee80211n=0
> > ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40]
> 
> ieee80211n should be 1 to enable 11n.
> 
> > If I disable 802.11n on the access point everything works ok.
> > Interesting enough, access point machine never crashes. At one point
> > both access point and client machine ran identical code and client
> > would always crash while the access point box would stay up. So
> > upgraded client to the latest and greatest and tried a few versions in
> > between, this panic has been very consistent. It always panics right
> > after 1st attempt to associate.
> > 
> > I was able to narrow down the panic to this assert ath_rc_ratefind_ht() in rc.c:
> >         ASSERT((rate_table->info[rate].valid && !ath_rc_priv->single_stream) ||
> >                (rate_table->info[rate].valid_single_stream &&
> >                 ath_rc_priv->single_stream));
> > When I ifdef'ed this assert panic went away and everything sort of
> > worked (haven't tested it heavily), but the performance dropped to
> > about 700Kbps. I usually get 10x when 802.11n is off and there is no
> > panic.
> > 
> > Has anyone else seen this?
> 
> A couple of bugs were fixed dealing with this issue, but looks like more
> lurk around. Can you attach the hostapd.conf, hostapd logs (hostapd -d),
> client side kernel logs [1] ?, from loading the driver to the point when you associate
> and get the panic.
> 
> [1]: See http://wireless.kernel.org/en/users/Drivers/ath9k on how to enable debug.
> 

Oh, and using debug=0x2000 would be sufficient.

Sujith

[ath9k-devel] ath9k panic when connecting to 802.11n-enabled AP

[Sujith]

Vladimir Senkov wrote:
> I've attempted to collect some data.
> However, It is never as simple as one would hope :(
> I'm attaching a tarball that contains logs and a patch, the latter is
> just to show where I've added my printk.

[ath9k-devel] Slow data rate in 11n when client connects in 20mhz mode.

[Valmantas Palikša]

Ok, so here's my setup
AP - D-link dwa-547 pci card in AP mode
client - iwlagn (iwl4965)

Latest compat-wireless on both machines.

When i set ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40] in hostapd, client
connects fine, but datarates are quite bad, about ~1-2MB/s. In contrast
when i set htcapab= , I get about 5-9MB/s when transferring AP->client.

PS. The intel card does not support 40mhz in 2.4ghz band.

[ath9k-devel] Slow data rate in 11n when client connects in 20mhz mode.

[Jouni Malinen]

On Mon, 2009-03-16 at 05:35 -0700, Valmantas Palik?a wrote:
> When i set ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40] in hostapd, client
> connects fine, but datarates are quite bad, about ~1-2MB/s. In contrast
> when i set htcapab= , I get about 5-9MB/s when transferring AP->client.
> 
> PS. The intel card does not support 40mhz in 2.4ghz band.

Which hostapd version are you using? I would recommend running a test
with the current development snapshot (0.7.x) from the git tree to get a
bug fix that resolves some issues related to negotiated HT capabilities.

- Jouni

[ath9k-devel] Slow data rate in 11n when client connects in 20mhz mode.

[Valmantas Paliksa]

On Mon, 2009-03-16 at 15:21 +0200, Jouni Malinen wrote:
> On Mon, 2009-03-16 at 05:35 -0700, Valmantas Palik?a wrote:
> > When i set ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40] in hostapd, client
> > connects fine, but datarates are quite bad, about ~1-2MB/s. In contrast
> > when i set htcapab= , I get about 5-9MB/s when transferring AP->client.
> > 
> > PS. The intel card does not support 40mhz in 2.4ghz band.
> 
> Which hostapd version are you using? I would recommend running a test
> with the current development snapshot (0.7.x) from the git tree to get a
> bug fix that resolves some issues related to negotiated HT capabilities.
> 
> - Jouni
> 
> 

I'm running latest git.

[ath9k-devel] Slow data rate in 11n when client connects in 20mhz mode.

[Valmantas Palikša]

On Mon, 2009-03-16 at 15:21 +0200, Jouni Malinen wrote:
> On Mon, 2009-03-16 at 05:35 -0700, Valmantas Palik?a wrote:
> > When i set ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40] in hostapd, client
> > connects fine, but datarates are quite bad, about ~1-2MB/s. In contrast
> > when i set htcapab= , I get about 5-9MB/s when transferring AP->client.
> > 
> > PS. The intel card does not support 40mhz in 2.4ghz band.
> 
> Which hostapd version are you using? I would recommend running a test
> with the current development snapshot (0.7.x) from the git tree to get a
> bug fix that resolves some issues related to negotiated HT capabilities.
> 
> - Jouni
> 
> 
> _______________________________________________
> ath9k-devel mailing list
> ath9k-devel at lists.ath9k.org
> https://lists.ath9k.org/mailman/listinfo/ath9k-devel


I'm running latest git.

[ath9k-devel] ath9k panic when connecting to 802.11n-enabled AP

[Vladimir Senkov]

On Mon, Mar 16, 2009 at 2:03 AM, Sujith <Sujith.Manoharan@atheros.com> wrote:
> handle_assoc STA 00:23:4d:b7:98:e8 - no HT, num of non-HT stations 1
> hostapd_ht_operation_update current operation mode=0x0
> hostapd_ht_operation_update new operation mode=0x13 changes=2
>  new AID 1
> wlan0: STA 00:23:4d:b7:98:e8 IEEE 802.11: association OK (aid 1)
>
> This is weird, since it chooses non-HT mode for the STA.
> Am not sure why this is happening. Are you running the latest git
> code for all 3 cases ?
>
> * hostapd
> * ath9k - AP side
> * ath9k - STA side

Not exactly, client is crashing and AP is stable, so I started with
upgrading the client.
ap:
kernel 2.6.27-gentoo-r8
compat-wireless-2009-03-09
hostapd v0.6.8

Client kernel and wireless were at the latest at the time of reporting
(2.6.29-rc7-wl):
supplicant is v0.6.4 I also tried v0.6.8 with identical results.
wpa_supplicant is running -Dwext, maybe that's part of the problem?
I've tried building 0.6.8 with NL80211 driver but that didn't work so
I left it with wext since this is how it came in the distro.

> Also, can you paste your hostapd.conf and wpa_supplicant's configuration file here ?

here is the wpa_supplicant.conf:
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=0
eapol_version=1
ap_scan=1
network={
        ssid="e8secure"
        proto=WPA2
        key_mgmt=WPA-PSK
        pairwise=CCMP
        group=CCMP
        psk="test12345"
        priority=1
}

here is the hostapd.conf:
interface=wlan0
driver=nl80211
logger_syslog=-1
logger_syslog_level=2
logger_stdout=-1
logger_stdout_level=2
dump_file=/tmp/hostapd.dump
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=e8secure
hw_mode=g
channel=3
beacon_int=100
dtim_period=2
max_num_sta=255
rts_threshold=2347
fragm_threshold=2346
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wme_enabled=0
wme_ac_bk_cwmin=4
wme_ac_bk_cwmax=10
wme_ac_bk_aifs=7
wme_ac_bk_txop_limit=0
wme_ac_bk_acm=0
wme_ac_be_aifs=3
wme_ac_be_cwmin=4
wme_ac_be_cwmax=10
wme_ac_be_txop_limit=0
wme_ac_be_acm=0
wme_ac_vi_aifs=2
wme_ac_vi_cwmin=3
wme_ac_vi_cwmax=4
wme_ac_vi_txop_limit=94
wme_ac_vi_acm=0
wme_ac_vo_aifs=2
wme_ac_vo_cwmin=2
wme_ac_vo_cwmax=3
wme_ac_vo_txop_limit=47
wme_ac_vo_acm=0
ap_max_inactivity=36000
ieee80211n=1
ht_capab=[HT40+][SHORT-GI-40][DSSS_CCK-40]
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1
wpa=2
wpa_psk_file=/etc/hostapd/hostapd.wpa_psk
wpa_key_mgmt=WPA-PSK
rsn_pairwise=CCMP
wpa_group_rekey=36000
wpa_strict_rekey=0

-- 
Regards,
Vladimir

[ath9k-devel] ath9k panic when connecting to 802.11n-enabled AP

[Sujith]

Vladimir Senkov wrote:
> On Mon, Mar 16, 2009 at 2:03 AM, Sujith <Sujith.Manoharan@atheros.com> wrote:
> > handle_assoc STA 00:23:4d:b7:98:e8 - no HT, num of non-HT stations 1
> > hostapd_ht_operation_update current operation mode=0x0
> > hostapd_ht_operation_update new operation mode=0x13 changes=2
> >  new AID 1
> > wlan0: STA 00:23:4d:b7:98:e8 IEEE 802.11: association OK (aid 1)
> >
> > This is weird, since it chooses non-HT mode for the STA.
> > Am not sure why this is happening. Are you running the latest git
> > code for all 3 cases ?
> >
> > * hostapd
> > * ath9k - AP side
> > * ath9k - STA side
> 
> Not exactly, client is crashing and AP is stable, so I started with
> upgrading the client.
> ap:
> kernel 2.6.27-gentoo-r8
> compat-wireless-2009-03-09
> hostapd v0.6.8

I would suggest that you use the latest git version for both hostapd
and ath9k (AP side).

Sujith

[ath9k-devel] ath9k panic when connecting to 802.11n-enabled AP

[Vladimir Senkov]

Sujith,

> I would suggest that you use the latest git version for both hostapd
> and ath9k (AP side).

I've started with upgrading ap  hostapd to the latest.
That has "fixed"/masked the crash on the client but the client can
only connect to hostapd when 802.11n is disabled on hostapd. Once I
enable 802.11n in hostapd.conf client can no longer authenticate.
I'm in the process of updating ath9k on the server and I also wanted
to run more tests (i.e. w/o WPA, etc), so this is an interim update,
I'll keep you posted.

-- 
Regards,
Vladimir

[ath9k-devel] ath9k panic when connecting to 802.11n-enabled AP

[Vladimir Senkov]

Sujith,

>> I would suggest that you use the latest git version for both hostapd
>> and ath9k (AP side).

I've updated everything to the latest as of tonight and ran some more tests.
Good news is that there are no oopses so far.
Bad news is that 802.11N still isn't very useful at all.

I turned off WPA2, everything is cleartext.
I removed wpa_supplicant from the client machine.

If 802.11n is turned off in hostapd everything works fine.
If I turn it on, station gets associated and hostapd debug still says
that HT=0, however traffic works only in one direction, from hostapd
to the client, but not in the direction from client to the hostapd.

When I boot this client machine into XP (making no changes to the
AP/hostapd) it comes up and gets connected at what it says is 300Mbps,
and hostapd debug no longer says that HT=0.

However ttcp test shows only 700KBps from client to hostapd and
~2500KBps from hostapd to the client. I get about the same (~2500KBps)
in both directions if I turn 802.11n off at the hostapd.

Regards.
Vladimir.