From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [BUG] XEN domU crash when PV grub chainloads 32-bit domU grub Date: Tue, 22 Sep 2015 09:52:35 +0100 Message-ID: <1442911955.10338.116.camel@citrix.com> References: <5600628A.20202@zappa.cx> <560101D2.5060005@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <560101D2.5060005@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Andrew Cooper , Andreas Sundstrom , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Tue, 2015-09-22 at 08:22 +0100, Andrew Cooper wrote: > > The segment registers indicate that the domU is executing in ring1 which > makes it a 32bit guest (also why 32bit words are used for the stack > dump), but r10 through r14 have 64bit values in. r10..r14 are not visible to 32-bit guests but it appears that this dumping function in Xen doesn't check for that and omit printing them. I suspect that if these were zeroed or poisoned upon domain creation you would see those values unmodified here. > It does appear to be an intermittent bug in 32bit grub-xen in the > eventual domU, but I have no help to offer with respect to debugging > grub-xen further. Me neither. I did suggest to Andreas that he also took it to grub-devel. I'll reply to the original with a full quote and copy that list. Ian.