From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751440AbdBXKAH (ORCPT ); Fri, 24 Feb 2017 05:00:07 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35582 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751365AbdBXJ77 (ORCPT ); Fri, 24 Feb 2017 04:59:59 -0500 Date: Fri, 24 Feb 2017 10:59:51 +0100 From: Greg KH To: "Herongguang (Stephen)" Cc: Paolo Bonzini , Chris Friesen , "Han, Huaitong" , "hangaohuai@huawei.com" , stable@vger.kernel.org, "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" , linux-kernel@vger.kernel.org Subject: Re: [Qemu-devel] kvm bug in __rmap_clear_dirty during live migration Message-ID: <20170224095951.GA11626@kroah.com> References: <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> <58AFFE55.20306@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <58AFFE55.20306@huawei.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 24, 2017 at 05:35:17PM +0800, Herongguang (Stephen) wrote: > > > On 2017/2/24 10:23, Herongguang (Stephen) wrote: > > > > > > On 2017/2/22 22:43, Paolo Bonzini wrote: > > > > > > > > > On 22/02/2017 14:31, Chris Friesen wrote: > > > > > > > > > > > > > > > > Can you reproduce it with kernel 4.8+? I'm suspecting commmit > > > > > 4e59516a12a6 ("kvm: vmx: ensure VMCS is current while enabling PML", > > > > > 2016-07-14) to be the fix. > > > > > > > > I can't easily try with a newer kernel, the software package we're using > > > > has kernel patches that would have to be ported. > > > > > > > > I'm at a conference, don't really have time to set up a pair of test > > > > machines from scratch with a custom kernel. > > > > > > 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. > > Hi, Greg, can you cherry pick commit 4e59516a12a6ef6dcb660cb3a3f70c64bd60cfec to 4.4-y? If the KVM maintainers say it is ok to do so, yes, I will. thanks, greg k-h