From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265293AbTFUTlq (ORCPT ); Sat, 21 Jun 2003 15:41:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265298AbTFUTlq (ORCPT ); Sat, 21 Jun 2003 15:41:46 -0400 Received: from crack.them.org ([146.82.138.56]:35306 "EHLO crack.them.org") by vger.kernel.org with ESMTP id S265293AbTFUTld (ORCPT ); Sat, 21 Jun 2003 15:41:33 -0400 Date: Sat, 21 Jun 2003 15:55:31 -0400 From: Daniel Jacobowitz To: "Udo A. Steinberg" Cc: Linux Kernel Mailing List Subject: Re: ptrace Issues Message-ID: <20030621195531.GA25700@nevyn.them.org> Mail-Followup-To: "Udo A. Steinberg" , Linux Kernel Mailing List References: <20030509004759.46182eca.us15@os.inf.tu-dresden.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030509004759.46182eca.us15@os.inf.tu-dresden.de> User-Agent: Mutt/1.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 09, 2003 at 12:47:59AM +0200, Udo A. Steinberg wrote: > > Hi all, > > I have discovered that recently I can no longer attach via strace to > already running processes for a long time. Specifically I have a daemon which > sleeps in select and periodically wakes up from SIGALRM signals. As soon as a > signal hits, strace quits on 2.5.69, however, it works fine on 2.4.21-rc. > Can someone shed some light on what's going on? Sorry it took so long... > root@Corona:~> strace -p 527 > --- SIGSTOP (Stopped (signal)) --- > --- SIGSTOP (Stopped (signal)) --- > select(7, [0 3 6], [], NULL, NULL) = ? ERESTARTNOHAND (To be restarted) > --- SIGALRM (Alarm clock) --- > root@Corona:~> echo $? > 0 I can't explain why it works for you on 2.4.21-rc. Were they the same system and strace version? The short answer appears to be: this is a bug in strace, not a bug in the kernel. If you get 4.4.98, it'll work. There was an off-by-one bug in parsing /proc/%d/status for the list of signals. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer