From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933121AbZJIHXb (ORCPT ); Fri, 9 Oct 2009 03:23:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752503AbZJIHXb (ORCPT ); Fri, 9 Oct 2009 03:23:31 -0400 Received: from www.tglx.de ([62.245.132.106]:56946 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755864AbZJIHXa (ORCPT ); Fri, 9 Oct 2009 03:23:30 -0400 Date: Fri, 9 Oct 2009 09:22:49 +0200 (CEST) From: Thomas Gleixner To: wu Jianfeng cc: linux-kernel@vger.kernel.org Subject: Re: the select system call's implementation may have some bug in preempt kernel mode In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 9 Oct 2009, wu Jianfeng wrote: > > Right, but that does not cause the task to be scheduled out for ever. > > I don't know why ??? > the process state is TASK_INTERRUPTIBLE, and was scheduled out. > > if no one wake up it or any signals received, it will sleep for ever. > The process does't entered any file's wait queue at that point, so I > am sure no one will wake up it. > > Am i right? No. Did you actually read, what I wrote further down ? > > When the task is scheduled out at that point, it is not > > deactivated. It is preempted, which means it stays on the run queue > > despite of the TASK_INTERRUPTIBLE state and is scheduled back in later > > on. Thanks, tglx