From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751327AbdBXPKn (ORCPT ); Fri, 24 Feb 2017 10:10:43 -0500 Received: from mail5.windriver.com ([192.103.53.11]:42004 "EHLO mail5.wrs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253AbdBXPKi (ORCPT ); Fri, 24 Feb 2017 10:10:38 -0500 Message-ID: <58B04CD3.7010304@windriver.com> Date: Fri, 24 Feb 2017 09:10:11 -0600 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: "Herongguang (Stephen)" , Paolo Bonzini , "Han, Huaitong" , "hangaohuai@huawei.com" , CC: "kvm@vger.kernel.org" , "fangying1@huawei.com" , "xudong.hao@linux.intel.com" , "qemu-devel@nongnu.org" , "wangxinxin.wang@huawei.com" , "kai.huang@linux.intel.com" , "rkrcmar@redhat.com" , "guangrong.xiao@linux.intel.com" , Subject: Re: [Qemu-devel] kvm bug in __rmap_clear_dirty during live migration References: <589C7E96.9060905@huawei.com> <589D83CE.1090803@huawei.com> <589DDC05.9010807@windriver.com> <58AA51D6.6020508@huawei.com> <1487565495.3740.27.camel@intel.com> <58AD0094.90304@windriver.com> <4dd92012-626a-2d80-9adb-0be398f73eb1@redhat.com> <58AD92AE.6040502@windriver.com> <6c5567f4-192d-aefd-90e4-89f53479c24e@redhat.com> <58AF9921.6060201@huawei.com> In-Reply-To: <58AF9921.6060201@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [128.224.22.139] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/23/2017 08:23 PM, Herongguang (Stephen) wrote: > On 2017/2/22 22:43, Paolo Bonzini wrote: >> Hopefully Gaohuai and Rongguang can help with this too. >> >> Paolo >> >> . >> > Yes, we are looking into and testing this. > > I think this can result in any memory corruption, if VM1 writes its > PML buffer into VM2’s VMCS (since sched_in/sched_out notifier of VM1 > is not registered yet), then VM1 is destroyed (hence its PML buffer > is freed back to kernel), after that, VM2 starts migration, so CPU > logs VM2’s dirty GFNS into a freed memory, results in any memory corruption. > > As its severity, this commit > (http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4e59516a12a6ef6dcb660cb3a3f70c64bd60cfec) > > is eligible to back port to kernel stable. > Are we expecting that fix to resolve the original issue, or is it a separate issue that needs fixing in stable? Chris