From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 2 Oct 2001 21:19:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 2 Oct 2001 21:18:56 -0400 Received: from granger.mail.mindspring.net ([207.69.200.148]:60707 "EHLO granger.mail.mindspring.net") by vger.kernel.org with ESMTP id ; Tue, 2 Oct 2001 21:18:42 -0400 Subject: Re: 2.4.10/Preemt STOP bug From: Robert Love To: Justin A Cc: linux-kernel@vger.kernel.org In-Reply-To: <20011002205856.A19554@bouncybouncy.net> In-Reply-To: <20011002205856.A19554@bouncybouncy.net> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Evolution/0.14.99+cvs.2001.09.30.08.08 (Preview Release) Date: 02 Oct 2001 21:19:07 -0400 Message-Id: <1002071952.864.141.camel@phantasy> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2001-10-02 at 20:58, Justin A wrote: > It seems there is a bug in 2.4.10 or the preemptable patch that causes the STOP > signal to not work right 19 times out of 20 or so. > > This is most easily seen by running 'seq 1 100000' in a terminal and pressing > control Z or using kill -STOP the proccess stops, but the parent process never > comes back, kill -CONT has to be used in order to get the proccess back. > > CPU usage my be a factor in this, yes(1) backgrounds correctly more often then > seq does. > > There are no problems with fg/CONT. The problem is with the preemptible kernel patch... You need to be using a recent patch, this bug was fixed awhile back in an explicit patch (patch-rml-2.4.xx-preempt-ptrace-signal-fix-1). It was merged into the 2.4.10 patch with revision 5, and it is in all newer patches. You can get patches for 2.4.10, 2.4.11-pre2, and 2.4.10-ac3 (soon -ac4) at http://tech9.net/rml/linux They all fix this problem. -- Robert M. Love rml at ufl.edu rml at tech9.net