From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752123Ab1IZWPe (ORCPT ); Mon, 26 Sep 2011 18:15:34 -0400 Received: from cantor2.suse.de ([195.135.220.15]:43380 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751799Ab1IZWPd (ORCPT ); Mon, 26 Sep 2011 18:15:33 -0400 Date: Mon, 26 Sep 2011 15:15:11 -0700 From: Greg KH To: Oleg Nesterov Cc: Tejun Heo , Luke Macken , stable@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: <20110926221511.GB19769@suse.de> 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 Is this fix in Linus's tree already? If so, what's the git commit id? If not, please take a look at Documentation/stable_kernel_rules.txt for how to properly submit a patch to the stable tree. thanks, greg k-h