From owner-freebsd-hackers@FreeBSD.ORG Thu Nov 15 18:10:52 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 E9147196; Thu, 15 Nov 2012 18:10:52 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-la0-f54.google.com (mail-la0-f54.google.com [209.85.215.54]) by mx1.freebsd.org (Postfix) with ESMTP id F2F138FC20; Thu, 15 Nov 2012 18:10:51 +0000 (UTC) Received: by mail-la0-f54.google.com with SMTP id j13so1827087lah.13 for ; Thu, 15 Nov 2012 10:10:50 -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=LEWTr6tRSOnHjaTKdYVhTzng2rbGRQeojE+a+UG+OjE=; b=EikVC4ZmvKF47uo6JHKwdrpbgmn/pyHX4WWZ6K3niB07mVxoJv3/iy7IITGE4RCtqx QxsPJ1je/VXFOr2fkFDYE8bUJ4JTyM5VLtAztIYTCaM4QZBID50ANdH0W9sA7OopnBgs WzajBSb2DQdQULYNr2waFyqvCr3ZCExrpDKvrXUVCh2wi2mNv5X6biBRqaW/Ye0aSt5/ Y+yemPOGJCLxW7IkXbuZukfjd//nPk3n8UEGO3FbgsFhllPnPjLCxiNDceds5YgL/IZU gvZc8AOj8EOqS+DSs1PMrLv6p2FYJLai+SOSYpIasjrH9J10pUx4tL1ronP2uS/wZUVE zWEQ== MIME-Version: 1.0 Received: by 10.112.36.200 with SMTP id s8mr947677lbj.92.1353003050811; Thu, 15 Nov 2012 10:10:50 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.112.134.5 with HTTP; Thu, 15 Nov 2012 10:10:50 -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 18:10:50 +0000 X-Google-Sender-Auth: TBPzVA_QUUO44JqNNX09ms-iIoE 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 18:10:53 -0000 On 11/15/12, Adrian Chadd wrote: > On 15 November 2012 10:01, Attilio Rao wrote: >> 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. > > Would a comprimise be ok? Ie, if I pushed everything but the sysctl > upstream, and just defaulted it to always panic? > > That way my diff wouldn't have to be a big thing; I'd just add the sysctl. I cannot forbid you from doing anything, I'm just giving you my opinion as the person who co-authored current WITNESS and locking primitives code. I think what you want to do is dangerous and highly abusable, so I'm not in favor of it at all, in whatever form it is. I understand you want to minimize your development patchset with upstream, but I think this is certainly not the way to go. That's also why I never formalized the BLESSING mechanism in WITNESS, for example. I already see WITNESS_KDB as an abuse, but at least until we have a way to make specific LOR (based on file/line, unfortunately) to be marked as "harmless" there is no way we can get rid of WITNESS_KDB. Said all that, you are free to do what you want, but if you commit anything in this area make sure your patch is reviewed by someone else and to state my firm disagreement with this approach in the commit message. Attilio -- Peace can only be achieved by understanding - A. Einstein