Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 19 Aug 2002 13:34:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 19 Aug 2002 13:34:22 -0400 Received: from neon-gw-l3.transmeta.com ([63.209.4.196]:59922 "EHLO neon-gw.transmeta.com") by vger.kernel.org with ESMTP id ; Mon, 19 Aug 2002 13:34:22 -0400 Date: Mon, 19 Aug 2002 10:42:06 -0700 (PDT) From: Linus Torvalds To: Ingo Molnar cc: linux-kernel@vger.kernel.org Subject: Re: [patch] O(1) sys_exit(), threading, scalable-exit-2.5.31-A6 In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1079 Lines: 26 Hmm.. This looks good, but I wonder if the real problem isn't really that our ptrace approach has always been kind of flaky. Basically, we started with the notion that only parents can trace their children, so no reparenting was ever needed. Then PTRACE_ATTACH came along, and we did the reparenting, and I think _that_ is where we made our big mistake. We sh ould just have made a separate "tsk->tracer" pointer, instead of continuing with the perverted "my parent is my tracer" logic. We shouldn't really re-write the parent/child relationship just because we're being traced. I'd be happy to apply this patch (well, your fixed version), but I think I'd prefer even more to make the whole reparenting go away, and keep the child list valid all through the lifetime of a process. How painful could that be? Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/