From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: linux-next: add utrace tree Date: Tue, 26 Jan 2010 22:02:32 +0100 Message-ID: <20100126210232.GF6567@basil.fritz.box> References: <20100122200129.GG22003@redhat.com> <20100122221348.GA4263@redhat.com> <877hr4g49l.fsf@basil.nowhere.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from one.firstfloor.org ([213.235.205.2]:39826 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751710Ab0AZVCe (ORCPT ); Tue, 26 Jan 2010 16:02:34 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-next-owner@vger.kernel.org List-ID: To: Linus Torvalds Cc: Andi Kleen , tromey@redhat.com, Stephen Rothwell , Kyle Moffett , Peter Zijlstra , Peter Zijlstra , Fr??d??ric Weisbecker , Oleg Nesterov , Steven Rostedt , LKML , Arnaldo Carvalho de Melo , "Frank Ch. Eigler" , linux-next@vger.kernel.org, "H. Peter Anvin" , utrace-devel@redhat.com, Thomas Gleixner > The problem is that anything that is based on reparenting and signals is > fundamentally a "one parent only" kind of interface. See? I was actually thinking about that before I wrote the email. But when I did that i couldn't come up with a good scenario where multiple debuggers actually make sense. In a sense being a debugger is really a very "intimate" thing for process. Do you really want to have multiple of them messing with each other? If yes how would they know what to touch and what not? The only thing I could think of was "user space virtualization" (like old UML) together with a real debugger, but frankly these solutions all seemed like big race conditions to me anyways and should be better done in the kernel or below it, so I have a hard time taking them seriously. Can you think of any scenario where multiple debuggers on a process make sense? -Andi