From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yunfeng Zhao Subject: Re: KVM Test result, kernel ff5bdac.., userspace eb2fd67.. -- OneNew Issue Date: Thu, 12 Jun 2008 17:25:33 +0800 Message-ID: <4850EB8D.7050301@intel.com> References: <20080609212310.GA6324@dmt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: john cooper , Chris Wright , kvm@vger.kernel.org, Avi Kivity To: Marcelo Tosatti Return-path: Received: from mga09.intel.com ([134.134.136.24]:63298 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752670AbYFLJZ4 (ORCPT ); Thu, 12 Jun 2008 05:25:56 -0400 In-Reply-To: <20080609212310.GA6324@dmt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: > On Fri, Jun 06, 2008 at 11:11:12AM +0800, Yunfeng Zhao wrote: > >> Hi All, >> >> This is today's KVM test result against kvm.git >> ff5bdac4be0230e0bb33e4208ac0a91343c72929 and kvm-userspace.git >> eb2fd67cbecdb573f908697ed41b81ee312372bd. >> >> One New Issue: >> ================================================ >> 1. Guests crash while rebooting >> https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1976075&group_id=180599 >> >> >> Five Old Issues: >> ================================================ >> 2. Fail to save restore and live migrate >> https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1976075&group_id=180599 >> 3. netperf causes linux guest with virtnet kernel panic >> https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1972449&group_id=180599 >> 4. XP crashes while rebooting >> https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1959452&group_id=180599 >> 5.Cannot boot guests with hugetlbfs >> https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1941302&group_id=180599 >> > > This is a get_user_pages() with hugetlb-vma's bug, not KVM's problem, > fixed by: > > commit 5b23dbe8173c212d6a326e35347b038705603d39 > Author: Adam Litke > Date: Wed Nov 14 16:59:33 2007 -0800 > > hugetlb: follow_hugetlb_page() for write access > > When calling get_user_pages(), a write flag is passed in by the caller to > indicate if write access is required on the faulted-in pages. > > Currently, follow_hugetlb_page() ignores this flag and always faults pages for > read-only access. This can cause data corruption because a device driver > that calls get_user_pages() with write set will not expect COW faults to > occur on the returned pages. > > This patch passes the write flag down to follow_hugetlb_page() and makes > sure hugetlb_fault() is called with the right write_access parameter. > > Can you please upgrade your test hosts to 2.6.25 or newer? > I tried to test it against 2.6.25-rc5. The host hanged while booting a xp guest. Thanks Yunfeng > Perhaps kvm-userspace should check for kernel version and disable > hugetlb backed memory. Nasty. > > Thanks John for help in tracking this down. > >