From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936310Ab3DQC4O (ORCPT ); Tue, 16 Apr 2013 22:56:14 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:42666 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936189Ab3DQC4M (ORCPT ); Tue, 16 Apr 2013 22:56:12 -0400 Message-ID: <516E0F1E.5090805@linux.vnet.ibm.com> Date: Wed, 17 Apr 2013 10:55:26 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Robin Holt CC: Andrew Morton , Marcelo Tosatti , Gleb Natapov , Avi Kivity , Andrea Arcangeli , LKML , KVM , Linux Memory Management List Subject: Re: [PATCH] mm: mmu_notifier: re-fix freed page still mapped in secondary MMU References: <516CF235.4060103@linux.vnet.ibm.com> <20130416093131.GJ3658@sgi.com> <516D275C.8040406@linux.vnet.ibm.com> <20130416112553.GM3658@sgi.com> <20130416114322.GN3658@sgi.com> <516D4D08.9020602@linux.vnet.ibm.com> <20130416180835.GY3658@sgi.com> In-Reply-To: <20130416180835.GY3658@sgi.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit x-cbid: 13041702-0260-0000-0000-000002D1F085 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/17/2013 02:08 AM, Robin Holt wrote: > On Tue, Apr 16, 2013 at 09:07:20PM +0800, Xiao Guangrong wrote: >> On 04/16/2013 07:43 PM, Robin Holt wrote: >>> Argh. Taking a step back helped clear my head. >>> >>> For the -stable releases, I agree we should just go with your >>> revert-plus-hlist_del_init_rcu patch. I will give it a test >>> when I am in the office. >> >> Okay. Wait for your test report. Thank you in advance. >> >>> >>> For the v3.10 release, we should work on making this more >>> correct and completely documented. >> >> Better document is always welcomed. >> >> Double call ->release is not bad, like i mentioned it in the changelog: >> >> it is really rare (e.g, can not happen on kvm since mmu-notify is unregistered >> after exit_mmap()) and the later call of multiple ->release should be >> fast since all the pages have already been released by the first call. >> >> But, of course, it's great if you have a _light_ way to avoid this. > > Getting my test environment set back up took longer than I would have liked. > > Your patch passed. I got no NULL-pointer derefs. Thanks for your test again. > > How would you feel about adding the following to your patch? I prefer to make these changes as a separate patch, this change is the improvement, please do not mix it with bugfix. You can make a patchset (comments improvement and this change) based on my fix.