From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753737Ab1CUQSm (ORCPT ); Mon, 21 Mar 2011 12:18:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46675 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752173Ab1CUQSk (ORCPT ); Mon, 21 Mar 2011 12:18:40 -0400 Date: Mon, 21 Mar 2011 17:09:03 +0100 From: Oleg Nesterov To: Tejun Heo Cc: roland@redhat.com, jan.kratochvil@redhat.com, vda.linux@googlemail.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, indan@nul.nu Subject: Re: [PATCH 3/8] job control: Fix ptracer wait(2) hang and explain notask_error clearing Message-ID: <20110321160903.GA26520@redhat.com> References: <1299614199-25142-1-git-send-email-tj@kernel.org> <1299614199-25142-4-git-send-email-tj@kernel.org> <20110321151941.GA20917@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110321151941.GA20917@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/21, Oleg Nesterov wrote: > > On 03/08, Tejun Heo wrote: > > > > + if (likely(!ptrace) || (wo->wo_flags & WCONTINUED)) > > + wo->notask_error = 0; > > I don't understand this part. Suppose that this task is not traced and > its real parent does do_wait(WEXITED). We shouldn't return -ECHLD in > this case (EXIT_ZOMBIE && delay_group_leader()). Argh. please ingnore this part. I misread the code above. > If the task is traced and debugger does do_wait(WEXITED) we should not > return -ECHLD too. Still true, or I missed something again... Oleg.