Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751127AbWC0U6l (ORCPT ); Mon, 27 Mar 2006 15:58:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751405AbWC0U6l (ORCPT ); Mon, 27 Mar 2006 15:58:41 -0500 Received: from mail.tv-sign.ru ([213.234.233.51]:45227 "EHLO several.ru") by vger.kernel.org with ESMTP id S1751127AbWC0U6k (ORCPT ); Mon, 27 Mar 2006 15:58:40 -0500 Date: Tue, 28 Mar 2006 03:55:30 +0400 From: Oleg Nesterov To: Thomas Gleixner Cc: Andrew Morton , linux-kernel@vger.kernel.org, mingo@elte.hu Subject: Re: [patch 2/2] hrtimer Message-ID: <20060327235530.GA7024@oleg> References: <20060325121219.172731000@localhost.localdomain> <20060325121223.966390000@localhost.localdomain> <20060325183213.63ab667c.akpm@osdl.org> <1143411016.5344.139.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1143411016.5344.139.camel@localhost.localdomain> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 708 Lines: 31 I also think this is racy. CPU_0 CPU_1 hrtimer_wakeup: task = t->task; t->task = NULL; <--- INTERRUPT ---> task is woken by signal, do_nanosleep() sees t->task == NULL, returns without hrtimer_cancel(), and __exits__. <--- RESUME ---> wake_up_process(task); Instead of exit(), 'task' can go to TASK_STOPPED or TASK_UNINTERRUPTIBLE after return from do_nanosleep(), it will be awakened by hrtimer_wakeup() unexpectedly. Oleg. - 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/