[ath9k-devel] ath9k queue hang

[Ben Greear <greearb@candelatech.com>]

On 04/14/2014 07:16 PM, Dave Taht wrote:
> We have been trying to replicate a bug in seeing wifi connections hanging
> in strange ways after tons of data is transferred... for several months now.
>
> The symptoms varied, anything from multicast failing to background or best
> effort traffic failing - from local access working with remote access
> not working...
>
> Last week, we finally got a situation where we had enough debugging on to see
> something that matches the symptoms we saw, in that one of the wifi queues
> would hang and leave the overlying qdisc full of packets that didn't drain.

Sounds familiar...I had a relatively clean patch in the 3.9 days, but had some
issues merging along the way and haven't bothered to rebase it, so patch is
not as clean as it used to be:

http://dmz2.candelatech.com/git/?p=linux-3.14.dev.y/.git;a=commitdiff;h=a34e34f46fbffc627dfc2d93c508f580fbaf29e2;hp=cce0d841338348c69ae6f7ef1b2bc8a6abea3fc4
http://dmz2.candelatech.com/git/?p=linux-3.14.dev.y/.git;a=commitdiff;h=3ecefa9c9f7eed21002dad7a6540d6d250297466;hp=134543c6fec7e28bf91272ce995b550b1bf73c62

I posted the patch to the mailing lists some time back..maybe a year or two ago.

If I recall, we could reproduce our problem fairly reliably by stepping an attenuator
in 10 db steps while under load.

I'd be curious to know if you try it out and it works for you...

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com