From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932163AbWHVKvK (ORCPT ); Tue, 22 Aug 2006 06:51:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932164AbWHVKvJ (ORCPT ); Tue, 22 Aug 2006 06:51:09 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:16868 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S932163AbWHVKvI (ORCPT ); Tue, 22 Aug 2006 06:51:08 -0400 Date: Tue, 22 Aug 2006 12:43:27 +0200 From: Ingo Molnar To: Oleg Nesterov Cc: Andrew Morton , Thomas Gleixner , Steven Rostedt , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] futex_find_get_task: remove an obscure EXIT_ZOMBIE check Message-ID: <20060822104327.GA28183@elte.hu> References: <20060821170604.GA1640@oleg> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060821170604.GA1640@oleg> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Oleg Nesterov wrote: > (Compile tested). > > futex_find_get_task: > > if (p->state == EXIT_ZOMBIE || p->exit_state == EXIT_ZOMBIE) > return NULL; > > I can't understand this. First, p->state can't be EXIT_ZOMBIE. The > ->exit_state check looks strange too. Sub-threads or tasks whose > ->parent ignores SIGCHLD go directly to EXIT_DEAD state (I am ignoring > a ptrace case). Why EXIT_DEAD tasks should be ok? Yes, EXIT_ZOMBIE is > more important (a task may stay zombie for a long time), but this > doesn't mean we should explicitely ignore other EXIT_XXX states. > > Signed-off-by: Oleg Nesterov i believe this is a remnant of older times when EXIT_ZOMBIE was introduced. We cloned that into the -rt tree, but then exit-state got cleaned up (by you) upstream and that cleanup didnt propagate into the -rt tree. Andrew: i think this is a must-have fix for v2.6.18. Acked-by: Ingo Molnar Ingo