From owner-freebsd-wireless@FreeBSD.ORG Mon Feb 20 02:47:32 2012 Return-Path: Delivered-To: freebsd-wireless@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0EEE3106566C for ; Mon, 20 Feb 2012 02:47:31 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-we0-f182.google.com (mail-we0-f182.google.com [74.125.82.182]) by mx1.freebsd.org (Postfix) with ESMTP id 2441F8FC16 for ; Mon, 20 Feb 2012 02:47:30 +0000 (UTC) Received: by werm13 with SMTP id m13so4686191wer.13 for ; Sun, 19 Feb 2012 18:47:30 -0800 (PST) Received-SPF: pass (google.com: domain of adrian.chadd@gmail.com designates 10.180.95.105 as permitted sender) client-ip=10.180.95.105; Authentication-Results: mr.google.com; spf=pass (google.com: domain of adrian.chadd@gmail.com designates 10.180.95.105 as permitted sender) smtp.mail=adrian.chadd@gmail.com; dkim=pass header.i=adrian.chadd@gmail.com Received: from mr.google.com ([10.180.95.105]) by 10.180.95.105 with SMTP id dj9mr13269129wib.18.1329706050270 (num_hops = 1); Sun, 19 Feb 2012 18:47:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; bh=7q6FaLBN6WV8T774dhT5DPpL+Bkd4YGdCtDZ6QYxcKI=; b=k6JL7o7dzU5xyr806taks8z2ZLUkTzYabbPxjXzT1KP0MkJ7QC55+/w2vTpm0CV84E jQJtEMxk0tDWAvg1fi6SYH6IBZJi82vp4U2X//ZDsyJvte6r0sfdg94U+JOzrUAVt6a0 gh/MhTucKN5rSUei0bmfnM/72pTR3QZR37SKU= MIME-Version: 1.0 Received: by 10.180.95.105 with SMTP id dj9mr11088164wib.18.1329706050213; Sun, 19 Feb 2012 18:47:30 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.216.154.199 with HTTP; Sun, 19 Feb 2012 18:47:30 -0800 (PST) In-Reply-To: <201202200243.q1K2h7Zi081981@freefall.freebsd.org> References: <201202200243.q1K2h7Zi081981@freefall.freebsd.org> Date: Sun, 19 Feb 2012 18:47:30 -0800 X-Google-Sender-Auth: tg698vtCoDW9YYmgQd8HZLP1o6g Message-ID: From: Adrian Chadd To: freebsd-wireless@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Subject: Re: kern/165306: [ath] race conditions between scanning and beacon timeout programming X-BeenThere: freebsd-wireless@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Discussions of 802.11 stack, tools device driver development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 20 Feb 2012 02:47:32 -0000 On 19 February 2012 18:43, wrote: > Synopsis: [ath] race conditions between scanning and beacon timeout programming This bug is ridiculously subtle and took me a while to figure out what was going on. Grr. I'm very tempted to just always flip on the beacon interrupt programming by writing the last known TSF if there was one, then updating it the next time we see a beacon. That way we don't end up in this situation where we never register that the AP has disappeared. Comments? Adrian