From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x22d.google.com (mail-qt0-x22d.google.com [IPv6:2607:f8b0:400d:c0d::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id D20273BA8D for ; Thu, 5 Jan 2017 09:03:13 -0500 (EST) Received: by mail-qt0-x22d.google.com with SMTP id l7so1906375qtd.1 for ; Thu, 05 Jan 2017 06:03:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tieto.com; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=ogrIQPP+8pL4ddBUsdtm2X//eeEJKWqjRKC1kDaQvkM=; b=KdcJvyUklWweB0O7QGwMPPqU62BTgS0iVswqTWlijiL4gyvOzsW/sBgBjQZrGD/khR mTDevYW5+FlwlVI+Rzlpqem/w7zAEeAd/Zg6ReiLM1BFBB7eNPQ4fExbHospA3g/dQaP 13oGnEvlbASEw1qahrGbqnSA1fF9Cp13bbPps= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=ogrIQPP+8pL4ddBUsdtm2X//eeEJKWqjRKC1kDaQvkM=; b=dAZ3ZvQ+gvHUQ7W3cANlNtQgZhCwrQNHDYk4ruhksdGOiECKmsCgs5RfRaSoEtW14y TFnuJNyyo8IFu5KBKvjsR7tR3uA3RupBroVvk70WCR4WxYGJGki+txkSpZVmNGKE1BDr WjgqQmTwX7Hu0YiD6tHWXRzjDF62WZTUsembwFXzHK6fZTm49iWvjTyVEjn3dO5m+b2/ OVOMjoXexJROvx2vCnAfJGb0kXFlLJ1oUl6ng0Kxq3YKHJPrw8idrPqXCHRELv2hTfVT 6iFCm+9Mt+AuTixxZABaV0OcmqIU3Y0ua6NP0IeUpSDpK6kgfGdUGsQ1Ck+kjX0nYxcu Yv7g== X-Gm-Message-State: AIkVDXKSHmM1hWwYqTo4hdZx1KsvW34LdXTQqG9AYh7/AvibmfTYVBGzyBgGKDG6VMBST4JGGspS/Atvpv/TKBdk7jUxXVr3r2Q3h7qtCXP8LnWl2P48ccV1JT9W9Bzwv64O5psFlyyFEIQ4BolXJbi1UTLxrcCIvQXRRA== X-Received: by 10.237.47.227 with SMTP id m90mr67159228qtd.120.1483624993467; Thu, 05 Jan 2017 06:03:13 -0800 (PST) MIME-Version: 1.0 Received: by 10.200.46.150 with HTTP; Thu, 5 Jan 2017 06:03:12 -0800 (PST) In-Reply-To: <46229222-ccb9-549d-578d-a8f4c9b83de4@nbd.name> References: <46229222-ccb9-549d-578d-a8f4c9b83de4@nbd.name> From: Michal Kazior Date: Thu, 5 Jan 2017 15:03:12 +0100 Message-ID: To: Felix Fietkau Cc: Loganaden Velvindron , Dave Taht , make-wifi-fast@lists.bufferbloat.net, LEDE Development List Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-DomainID: tieto.com Subject: Re: [Make-wifi-fast] ath9k airtime fairness stabiity issues? X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Jan 2017 14:03:13 -0000 On 5 January 2017 at 14:23, Felix Fietkau wrote: > On 2017-01-05 14:22, Loganaden Velvindron wrote: >> On Thu, Jan 5, 2017 at 4:59 PM, Dave Taht wrote: >>> Felix: >>> >>> Was there a bugreport? (don't see one) >>> >>> Do you have a specific device or behavior triggering this revert? >>> >>> >>> On Thu, Jan 5, 2017 at 4:42 AM, Dave Taht wrote: >>>> https://github.com/lede-project/source/commit/c296ba834db4ce8c71e0ad70= 30aab188fe60b27b >>> >>> >> >> Hi nbd & Toke, >> >> Would it be possible to enable it only on platforms like the tp-link >> archer c7 v2 and the ubnt, where we have confirmed test reports for >> the upcoming release ? > I think it's quite unlikely that these issues are hardware specific. > It's probably more related to the environment, types of clients, or even > traffic patterns. Some people are complaining ath10k is unstable for them when wake_tx_queue is enabled. I suspect the ATF problem in ath9k might be providing extra opportunities to hit the same bug. I think RCU is not properly handled. txq_info shares lifecycle of sta_info and should therefore be protected in the same manner. When you queue up ieee80211_txq in a driver and use it later you effectively break RCU. Grabbing rcu_read_lock() *later*, e.g. when re-scheduling tx is not sufficient to protect from the possible race of part1/part2 of station destroying logic and driver accessing its internal txq list. There seems to be a mechanism to hook up with to fix that already - drv_sta_pre_rcu_remove(). I've been seldom looking at the ath10k problem and noticed this bit. I didn't get a chance (and probably won't, any time soon) to take a closer look, nor test/verify it for that matter. Micha=C5=82