From owner-freebsd-current Thu May 10 10: 6:34 2001 Delivered-To: freebsd-current@freebsd.org Received: from meow.osd.bsdi.com (meow.osd.bsdi.com [204.216.28.88]) by hub.freebsd.org (Postfix) with ESMTP id 805FF37B422; Thu, 10 May 2001 10:06:27 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: from laptop.baldwin.cx (john@jhb-laptop.osd.bsdi.com [204.216.28.241]) by meow.osd.bsdi.com (8.11.2/8.11.2) with ESMTP id f4AH6NG86631; Thu, 10 May 2001 10:06:23 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Thu, 10 May 2001 10:05:29 -0700 (PDT) From: John Baldwin To: Robert Watson Subject: Re: pgm to kill 4.3 via vm Cc: freebsd-current@FreeBSD.org, Garrett Wollman Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 10-May-01 Robert Watson wrote: > > On Wed, 9 May 2001, Garrett Wollman wrote: > >> <> said: >> >> > I followed everything here fine until you asserted that the debugger >> > shouldn't need any locks. >> >> When the debugger is running, everything else should have been >> forcibly halted. > > The process and signal-related structures may be inconsistent if the > debugger disregards existing locks held over those structures. It does > not matter if code is currently still executing, it matters that > preemption can occur. The choices appear to be: > > 1) Disregard locks and risk corruption If I'm sending a kill -9 to a program, I could really care less about clobbering the SIGABRT it is currently getting sent. :) I think that a kernel debugger is a case of where one allows much foot shooting to occur. > 2) Fail if a lock is held mtx_trylock() makes this relatively easy to implement in many cases. -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message