From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755579AbZBTDtt (ORCPT ); Thu, 19 Feb 2009 22:49:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751722AbZBTDtk (ORCPT ); Thu, 19 Feb 2009 22:49:40 -0500 Received: from mx1.redhat.com ([66.187.233.31]:51027 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751131AbZBTDtj (ORCPT ); Thu, 19 Feb 2009 22:49:39 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Oleg Nesterov X-Fcc: ~/Mail/linus Cc: Andrew Morton , Jerome Marchand , Denys Vlasenko , linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm 2/2] ptrace_untrace: fix the SIGNAL_STOP_STOPPED check In-Reply-To: Oleg Nesterov's message of Friday, 13 February 2009 11:54:42 +0100 <20090213105442.GA24328@redhat.com> References: <20090213105442.GA24328@redhat.com> X-Antipastobozoticataclysm: When George Bush projectile vomits antipasto on the Japanese. Message-Id: <20090220034928.741F6FC2F7@magilla.sf.frob.com> Date: Thu, 19 Feb 2009 19:49:28 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > This bug is ancient too. ptrace_untrace() must not resume the task > if the group stop in progress, we should set TASK_STOPPED instead. Right, the change looks correct. > Unfortunately, we still have problems here: > > - if the process/thread was traced, SIGNAL_STOP_STOPPED > does not necessary means this thread group is stopped. > > - ptrace breaks the bookkeeping of ->group_stop_count. Neither of these should be true today as I understand the code. So if you have reason to think these, I must be missing something that is likely to be relevant to reviewing this change. Thanks, Roland