From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932318Ab1JSXDu (ORCPT ); Wed, 19 Oct 2011 19:03:50 -0400 Received: from out5.smtp.messagingengine.com ([66.111.4.29]:57577 "EHLO out5.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755406Ab1JSXDr (ORCPT ); Wed, 19 Oct 2011 19:03:47 -0400 X-Sasl-enc: Bifw+XbWnxtnDEfwxRlDCmy6tosq430e7fmaRXL4Puw2 1319065426 Date: Wed, 19 Oct 2011 16:00:27 -0700 From: Greg KH To: Oleg Nesterov Cc: Greg KH , Tejun Heo , Luke Macken , stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH stable-3.0] ptrace: don't clear GROUP_STOP_SIGMASK on double-stop Message-ID: <20111019230027.GD32438@kroah.com> References: <20110926170632.GA16936@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110926170632.GA16936@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 26, 2011 at 07:06:32PM +0200, Oleg Nesterov wrote: > https://bugzilla.redhat.com/show_bug.cgi?id=740121 > > 1. Luke Macken triggered WARN_ON(!(group_stop & GROUP_STOP_SIGMASK)) > in do_signal_stop(). > > This is because do_signal_stop() clears GROUP_STOP_SIGMASK part > unconditionally but doesn't update it if task_is_stopped(). > > 2. Looking at this problem I noticed that WARN_ON_ONCE(!ptrace) is > not right, a stopped-but-resumed tracee can clone the untraced > thread in the SIGNAL_STOP_STOPPED group, the new thread can start > another group-stop. > > Remove this warning, we need more fixes to make it true. > > Reported-by: Luke Macken > Signed-off-by: Oleg Nesterov I still don't understand, did this fix ever get into Linus's tree? If so, what is the git commit id. If not, why not? I can't apply it to the 3.0-stable tree unless it is there, or there is a very good reason why it isn't. thanks, greg k-h