From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kip Macy Subject: Re: garbage registers when domain killed by xen Date: Sat, 7 May 2005 07:23:24 -0700 Message-ID: References: <1bea7043d407c09e23b119c6c278dbe3@cl.cam.ac.uk> Reply-To: Kip Macy Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: xen-devel List-Id: xen-devel@lists.xenproject.org There is an odd relationship between hitting the send button and epiphanies= . Show_guest_stack says the eip is 0 and the stack has eflags, eip, and CS over and over and over again. That would indicate that I'm running off my stack by trapping over and over again. However, I don't have traps or callback handlers installed. What may be happening is xen setting up a trapframe and then jumping to failsafe callback - over and over again because jumping to failsafe callback itself causes a page fault. In this case the eip is legitimately 0 - but not because of me but because xen isn't checking that I've actually set my failsafe_callback. I'll go look at FLT14 again to see if I'm on the right track. -Kip On 5/7/05, Kip Macy wrote: > I'm not sure about ecx/edx but I know eip is bad. There are legitimate > cases of trying to call a null function pointer, but I know from the > context that that isn't the case. It appears to be a page fault - but > I don't have trap handlers installed yet. >=20 > -Kip >=20 > On 5/7/05, Keir Fraser wrote: > > > > On 7 May 2005, at 02:26, Kip Macy wrote: > > > > > Is it really necessary for xen to overwrite part of a domain's contex= t > > > on a fatal trap? > > > > Which ones are overwritten -- ecx/edx? I'm not sure how that could > > happen but it's clearly a bug rather than intentional. > > > > -- Keir > > > > >