Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754649Ab0DFOi7 (ORCPT ); Tue, 6 Apr 2010 10:38:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39910 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752951Ab0DFOix (ORCPT ); Tue, 6 Apr 2010 10:38:53 -0400 Date: Tue, 6 Apr 2010 16:36:35 +0200 From: Oleg Nesterov To: Matt Helsley Cc: Roland McGrath , Grzegorz Nosek , Sukadev Bhattiprolu , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Biederman Eric Biederman Subject: Re: Testing lxc 0.6.5 in Fedora 13 Message-ID: <20100406143635.GA12315@redhat.com> References: <20100321195044.GA23757@megiteam.pl> <20100323212834.GH20796@count0.beaverton.ibm.com> <20100325213356.GB20541@megiteam.pl> <20100326111131.GA8604@redhat.com> <20100326115357.GA3345@count0.beaverton.ibm.com> <20100326124522.GD17113@megiteam.pl> <20100326134709.GB15790@redhat.com> <20100406034443.8B40ED477@magilla.sf.frob.com> <20100406135345.GC3345@count0.beaverton.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100406135345.GC3345@count0.beaverton.ibm.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: 1128 Lines: 34 On 04/06, Matt Helsley wrote: > > On Mon, Apr 05, 2010 at 08:44:43PM -0700, Roland McGrath wrote: > > > tracehook_report_clone_complete() call is made when that task_struct is no > > longer guaranteed to be valid. Hmm. I missed this. > Also, if utrace allows multiple tracers and they each > exist in a different namespace then storing a pid nr isn't going to work. Yes, but utrace is simple. ptrace_report_clone() does ctx->eventmsg = child->pid; we should fix this line and that is all, afaics. Every tracer has a separate "struct ptrace_context *ctx". > So my hunch is, in the long run, we'll need to hold a reference there and > drop it when the last tracer detaches Without utrace only one tracer is possible. So, I think we should either change do_fork() to get the right tracee_pid_nr, or add get/put into do_fork() and change tracehooks as Roland suggested. 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/