From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx107.postini.com [74.125.245.107]) by kanga.kvack.org (Postfix) with SMTP id E5EC46B0006 for ; Tue, 16 Apr 2013 22:55:39 -0400 (EDT) Received: from /spool/local by e23smtp02.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 17 Apr 2013 12:47:56 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id 1E3192CE8054 for ; Wed, 17 Apr 2013 12:55:32 +1000 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r3H2g4Sa46071826 for ; Wed, 17 Apr 2013 12:42:05 +1000 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r3H2tUfH027618 for ; Wed, 17 Apr 2013 12:55:30 +1000 Message-ID: <516E0F1E.5090805@linux.vnet.ibm.com> Date: Wed, 17 Apr 2013 10:55:26 +0800 From: Xiao Guangrong MIME-Version: 1.0 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 Sender: owner-linux-mm@kvack.org List-ID: To: Robin Holt Cc: Andrew Morton , Marcelo Tosatti , Gleb Natapov , Avi Kivity , Andrea Arcangeli , LKML , KVM , Linux Memory Management List 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org