<div dir="ltr"><div><div>No problem. Seemed like the driver freeze could be a rather difficult problem to diagnose (it was for me).<br><br></div>If you find node which seems to have one of its vif's locked up like this, but still have access to a local SSH/serial console, this command could tell if you if the driver is indeed stuck:<br>
<br></div>cat /sys/kernel/debug/ieee80211/phy*/ath9k/queues</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Jan 16, 2014 at 9:13 AM, Dan Staples <span dir="ltr"><<a href="mailto:danstaples@opentechinstitute.org" target="_blank">danstaples@opentechinstitute.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thanks very much for this heads up, Ben! I can't say we've seen this<br>
ourselves, but we also don't run a network with heavy load. If we get<br>
reports about this from our testbed networks, we'll definitely look into<br>
whether this is the cause.<br>
<br>
Dan<br>
<div><div class="h5"><br>
On 01/14/2014 04:05 PM, Ben West wrote:<br>
> Howdy,<br>
><br>
> Giving you a heads up about a problem I've encountered on UBNT<br>
> Nanostation Loco M2, Nanostation M5, and TP-Link TL-MR3020. WLAN<br>
> Slovenija also saw it on other TP-Link products. Good chance<br>
> Commotion-OpenWRT might be seeing this driver freeze, too.<br>
><br>
> Under heavy load conditions, the ath9k driver bundled with recent<br>
> versions of AA may freeze, and all broadcast SSIDs disappear. For me,<br>
> this was also causing additional weird side-effects like<br>
> hostapd/wpa_supplicant crashing, and olsrd complaining "OLSR: sendto<br>
> IPv4 Resource temporarily unavailable," depending on which vif happened<br>
> to lock up.<br>
><br>
> The lockup does appear to correlate well with heavy traffic load, i.e.<br>
> never see this problem on nodes with very light traffic. Also, it's<br>
> very intermittent. Nodes with a weekly reboot schedule might see this<br>
> lockup a couple times a month or so, in my experience.<br>
><br>
> This is the ticket filed in OpenWRT issue queue:<br>
> <a href="https://dev.openwrt.org/ticket/13681" target="_blank">https://dev.openwrt.org/ticket/13681</a><br>
><br>
> This is the updated version of mac80211 and hostapd which nbd has<br>
> offered to address the driver lockup issue under AA. I've reflashed my<br>
> affected problem nodes over the past couple weeks (AA r39154), and so<br>
> far so good. I presume these versions will eventually be backported<br>
> into AA.<br>
> <a href="http://nbd.name/gitweb.cgi?p=aa-mac80211.git;a=summary" target="_blank">http://nbd.name/gitweb.cgi?p=aa-mac80211.git;a=summary</a><br>
><br>
> Finally, this is the script from WLAN Slovenija to detect the freeze and<br>
> trigger a reboot. I've incorporated this script as-is in WasabiNet<br>
> firmware for Nanostation Loco M2s and the TL-MR3020s.<br>
> <a href="https://github.com/wlanslovenija/firmware-packages-opkg/blob/master/util/nodewatcher-watchdog/files/check_ath9k_freeze" target="_blank">https://github.com/wlanslovenija/firmware-packages-opkg/blob/master/util/nodewatcher-watchdog/files/check_ath9k_freeze</a><br>
><br>
> For Nanostation M5s, the string the check for is "qdepth: 0 ampdu-depth:<br>
> 0 pending: 124 stopped: 1".<br>
><br>
> --<br>
> Ben West<br>
> <a href="http://gowasabi.net" target="_blank">http://gowasabi.net</a><br>
</div></div>> <a href="mailto:ben@gowasabi.net">ben@gowasabi.net</a> <mailto:<a href="mailto:ben@gowasabi.net">ben@gowasabi.net</a>><br>
> <a href="tel:314-246-9434" value="+13142469434">314-246-9434</a><br>
><br>
><br>
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><br>
<span class="HOEnZb"><font color="#888888"><br>
--<br>
Dan Staples<br>
<br>
Open Technology Institute<br>
<a href="https://commotionwireless.net" target="_blank">https://commotionwireless.net</a><br>
OpenPGP key: <a href="http://disman.tl/pgp.asc" target="_blank">http://disman.tl/pgp.asc</a><br>
Fingerprint: 2480 095D 4B16 436F 35AB 7305 F670 74ED BD86 43A9<br>
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<br>
</font></span></blockquote></div><br><br clear="all"><br>-- <br>Ben West<div><a href="http://gowasabi.net" target="_blank">http://gowasabi.net</a><br><a href="mailto:ben@gowasabi.net" target="_blank">ben@gowasabi.net</a><br>
314-246-9434<br></div>
</div>