From owner-freebsd-hackers@FreeBSD.ORG Thu Nov 15 16:37:51 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 BE3E36B5; Thu, 15 Nov 2012 16:37:51 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by mx1.freebsd.org (Postfix) with ESMTP id 85F538FC0C; Thu, 15 Nov 2012 16:37:51 +0000 (UTC) Received: by mail-pa0-f54.google.com with SMTP id kp6so1279899pab.13 for ; Thu, 15 Nov 2012 08:37:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=Hax9OoliXpccxGrtLR2vkRCIXBxNG1yKwlvMk0RUXRc=; b=YUxsYsXpQYRrHi8ba8waS60qRly4mwRxmt8wvejHSObD5gp5uo0QLvl3gZUbH1yQQ9 mVZY647PS18OjpK3XpxHTyVDLu49JITMnAiZVqAppZB/nmBQxlvqYs6yi3yLM3ndQuEf Q6InGF7axUveopUVKrQATrsmzCNqTrT7/CiwJya0rjRFcFWk9cU0XLg3nsWWD/PKImGU rZo0u8E65t34ewA2anP9XQpPBqGbpVkAlCRyEVhh6unq8HmWKIh3wARjvy2ci1NdBefm XEA7z72KoiK4iF5oXVrJcpM63EEGltKsFabjzkX6v+WvMCKKM/fxYGt9C/NlGwccISku vTcA== MIME-Version: 1.0 Received: by 10.66.85.134 with SMTP id h6mr4714259paz.36.1352997471336; Thu, 15 Nov 2012 08:37:51 -0800 (PST) Sender: adrian.chadd@gmail.com Received: by 10.68.124.130 with HTTP; Thu, 15 Nov 2012 08:37:51 -0800 (PST) In-Reply-To: References: Date: Thu, 15 Nov 2012 08:37:51 -0800 X-Google-Sender-Auth: t1znI8gbjtaOqflWpgDKI8n8H7s Message-ID: Subject: Re: [RFQ] make witness panic an option From: Adrian Chadd To: Giovanni Trematerra Content-Type: text/plain; charset=ISO-8859-1 Cc: "freebsd-hackers@freebsd.org" , freebsd-arch@freebsd.org X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list 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 16:37:51 -0000 On 15 November 2012 05:27, Giovanni Trematerra wrote: > I really do think that is a very bad idea. > When a locking assertion fails you have just to stop your mind and > think what's wrong, > no way to postpone on this. Not all witness panics are actually fatal. For a developer who is sufficiently cluey in their area, they are quite likely able to just stare at the code paths for a while to figure out why the incorrectness occured. As I said, I do this primarily so I can sprinkle lots of lock owned/unowned assertions around my driver(s) and then use that to catch when things aren't being correct. Having to reboot upon _every_ lock assertion quickly got old. Adrian