From owner-freebsd-hackers@FreeBSD.ORG Thu Nov 15 18:01:19 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id E347678E; Thu, 15 Nov 2012 18:01:19 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-lb0-f182.google.com (mail-lb0-f182.google.com [209.85.217.182]) by mx1.freebsd.org (Postfix) with ESMTP id E8C6E8FC0C; Thu, 15 Nov 2012 18:01:17 +0000 (UTC) Received: by mail-lb0-f182.google.com with SMTP id gg13so1894894lbb.13 for ; Thu, 15 Nov 2012 10:01:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=47n18/O51NP7s5CydvLVUh0eppMNfXXPtS1svfyXOOg=; b=tB/cY1xKjHlShukor721m4HLSpkLxrNFUaOLsNOJDWZb5xZd0vM/sZ7dByyd4rur/B B29ORtErxXYPAVEge6mgvag4/IQ4PuWoQBHENjcS2BtGNGyWiEqLQZ8vIzib9QksD89j 1mdRhl3KksKXKvaTJC8W47oKCVXh3BqprvENuRn2cuCmdAIJC5F61EcUX48S4OYahnEM HOViSfVAvJDkL/o5le6/rE8zInKBnIY6aGzYmAEGoI4BpakMNwqtoZMXNE2RwiKetUx/ 9s04vLB6IwQfs/XB5rZ3GQ1duclDsbF1FclbM6+Wj0W1NYsnIoQ9u8nCx9B+0zc5Cpba 258g== MIME-Version: 1.0 Received: by 10.112.47.129 with SMTP id d1mr906520lbn.115.1353002476703; Thu, 15 Nov 2012 10:01:16 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.112.134.5 with HTTP; Thu, 15 Nov 2012 10:01:16 -0800 (PST) In-Reply-To: References: <1353001175.1217.153.camel@revolution.hippie.lan> <47374EC3-5022-49AC-A17E-7F234A88B5C6@bsdimp.com> Date: Thu, 15 Nov 2012 18:01:16 +0000 X-Google-Sender-Auth: ffz8GaTNpAB9qgttem20d2ZLAM0 Message-ID: Subject: Re: [RFQ] make witness panic an option From: Attilio Rao To: Adrian Chadd Content-Type: text/plain; charset=UTF-8 Cc: Ian Lepore , freebsd-arch@freebsd.org, freebsd-hackers@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Nov 2012 18:01:20 -0000 On 11/15/12, Adrian Chadd wrote: > On 15 November 2012 09:56, Warner Losh wrote: > >>> Do you really think that an abusable mechanism will help here rather > >> It sounds like he's more worried about introducing LoRs into his wireless >> code. They are harmless, for him, and he can fix them by reloading the >> driver. They are only harmful if he loses a race. > > LOR's and lock assertions. Ie, I want to find out at run time that a > lock wasnt' held at a certain position but continue soldiering on. > That's how I've been finding out all of the races in net80211/ath, as > there wasn't locking where there needed to be. I think that your worries are focused more around the latter than the former, which can be easilly shut down already today. And frankly I will never be in favor of a patch that automatically shutdowns lock assertion. Please patch your local code to do so but don't add any generic/upstream/all-around mechanism for that. Attilio -- Peace can only be achieved by understanding - A. Einstein