From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752926AbYCILtR (ORCPT ); Sun, 9 Mar 2008 07:49:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751063AbYCILtF (ORCPT ); Sun, 9 Mar 2008 07:49:05 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:48914 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751008AbYCILtE (ORCPT ); Sun, 9 Mar 2008 07:49:04 -0400 Date: Sun, 9 Mar 2008 12:48:44 +0100 From: Ingo Molnar To: WANG Cong Cc: linux-kernel@vger.kernel.org, gvaughan@jpl.nasa.gov, akpm@osdl.org, jeremy@goop.org Subject: Re: [PATCH] Fix check after use in kernel/exit.c Message-ID: <20080309114844.GC30331@elte.hu> References: <20080308.161105.253167431.xiyou.wangcong@gmail.com> <20080308083637.GA23555@elte.hu> <20080308085322.GA29628@elte.hu> <20080308.165821.119846418.xiyou.wangcong@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080308.165821.119846418.xiyou.wangcong@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: 0.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.5 required=5.9 tests=BAYES_40 autolearn=no SpamAssassin version=3.2.3 0.5 BAYES_40 BODY: Bayesian spam probability is 20 to 40% [score: 0.3569] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * WANG Cong wrote: > > actually, i unapplied it again because the patch is wrong: > > mm_release() has side-effects for kernel threads such as the > > deactivate_mm() [which is important even if the user-mm is NULL]. If > > the NULL mm dereference can really trigger then it should be avoided > > within mm_release(). > > Do you mean that the NULL check should be moved into mm_release()? yes - we need to run deactivate_mm() for kernel threads. Ingo