Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932727Ab0AFURd (ORCPT ); Wed, 6 Jan 2010 15:17:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932552Ab0AFURc (ORCPT ); Wed, 6 Jan 2010 15:17:32 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9203 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932305Ab0AFURb (ORCPT ); Wed, 6 Jan 2010 15:17:31 -0500 Date: Wed, 6 Jan 2010 21:17:22 +0100 From: Oleg Nesterov To: Martin Schwidefsky Cc: Roland McGrath , caiqian@redhat.com, Heiko Carstens , Jan Kratochvil , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, utrace-devel@redhat.com Subject: Re: s390 && user_enable_single_step() (Was: odd utrace testing results on s390x) Message-ID: <20100106201722.GB26204@redhat.com> References: <20100104155225.GA16650@redhat.com> <20100104171626.22ea2d9c@mschwide.boeblingen.de.ibm.com> <20100104181412.GA21146@redhat.com> <20100104211147.4CC94D532@magilla.sf.frob.com> <20100105105030.66bb8a0a@mschwide.boeblingen.de.ibm.com> <20100105153633.GA9376@redhat.com> <20100105164610.388effd3@mschwide.boeblingen.de.ibm.com> <20100105155913.GA10652@redhat.com> <20100105170301.GA13641@redhat.com> <20100105195818.GA20358@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100105195818.GA20358@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 Content-Length: 1636 Lines: 49 On 01/05, Oleg Nesterov wrote: > > On 01/05, Oleg Nesterov wrote: > > > > On 01/05, Oleg Nesterov wrote: > > > > > > I'll add clear_bit(TIF_SINGLE_STEP) into do_fork() path and re-test. > > > > Hmm. This patch > > > > --- kernel/fork.c~ 2009-12-22 10:41:53.188084961 -0500 > > +++ kernel/fork.c 2010-01-05 11:42:58.370636323 -0500 > > @@ -1206,6 +1206,8 @@ static struct task_struct *copy_process( > > * of CLONE_PTRACE. > > */ > > clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE); > > + clear_tsk_thread_flag(p, TIF_SINGLE_STEP); > > + user_disable_single_step(p); > > #ifdef TIF_SYSCALL_EMU > > clear_tsk_thread_flag(p, TIF_SYSCALL_EMU); > > #endif > > > > doesn't help, I still see the same XXX's in dmesg... > > Oh, now I am totally confused. > > I reverted your fix from > https://www.redhat.com/archives/utrace-devel/2010-January/msg00006.html > and now there is nothing in dmesg. I take this back. I re-tested this all under 2.6.32.2 + utrace, and I see nothing in dmesg. I don't know what I did wrong, most probably I forgot to do zipl or something like this... I'll try to summarize. Martin's patch from https://www.redhat.com/archives/utrace-devel/2010-January/msg00006.html fixes the problems with utrace. However, with or without CONFIG_UTRACE, 6580807da14c423f0d0a708108e6df6ebc8bc83d is needed on s390 too, otherwise the child gets unnecessary traps. 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/