[Commotion-dev] Alternate mac80211 / hostapd from nbd for ath9k driver freeze issue

[Dan Staples]

Thanks very much for this heads up, Ben! I can't say we've seen this
ourselves, but we also don't run a network with heavy load. If we get
reports about this from our testbed networks, we'll definitely look into
whether this is the cause.

Dan

On 01/14/2014 04:05 PM, Ben West wrote:
> Howdy,
> 
> Giving you a heads up about a problem I've encountered on UBNT
> Nanostation Loco M2, Nanostation M5, and TP-Link TL-MR3020.  WLAN
> Slovenija also saw it on other TP-Link products.  Good chance
> Commotion-OpenWRT might be seeing this driver freeze, too.
> 
> Under heavy load conditions, the ath9k driver bundled with recent
> versions of AA may freeze, and all broadcast SSIDs disappear.  For me,
> this was also causing additional weird side-effects like
> hostapd/wpa_supplicant crashing, and olsrd complaining "OLSR: sendto
> IPv4 Resource temporarily unavailable," depending on which vif happened
> to lock up.
> 
> The lockup does appear to correlate well with heavy traffic load, i.e.
> never see this problem on nodes with very light traffic.  Also, it's
> very intermittent.  Nodes with a weekly reboot schedule might see this
> lockup a couple times a month or so, in my experience.
> 
> This is the ticket filed in OpenWRT issue queue:
> https://dev.openwrt.org/ticket/13681
> 
> This is the updated version of mac80211 and hostapd which nbd has
> offered to address the driver lockup issue under AA.  I've reflashed my
> affected problem nodes over the past couple weeks (AA r39154), and so
> far so good.  I presume these versions will eventually be backported
> into AA.
> http://nbd.name/gitweb.cgi?p=aa-mac80211.git;a=summary
> 
> Finally, this is the script from WLAN Slovenija to detect the freeze and
> trigger a reboot.  I've incorporated this script as-is in WasabiNet
> firmware for Nanostation Loco M2s and the TL-MR3020s.
> https://github.com/wlanslovenija/firmware-packages-opkg/blob/master/util/nodewatcher-watchdog/files/check_ath9k_freeze
> 
> For Nanostation M5s, the string the check for is "qdepth: 0 ampdu-depth:
> 0 pending: 124 stopped: 1".
> 
> -- 
> Ben West
> http://gowasabi.net
> ben at gowasabi.net <mailto:ben at gowasabi.net>
> 314-246-9434
> 
> 
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-- 
Dan Staples

Open Technology Institute
https://commotionwireless.net
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