This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] BUG grant_table.c line 939

To: "King, Steven R" <steven.r.king@xxxxxxxxx>
Subject: Re: [Xen-devel] BUG grant_table.c line 939
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 24 Jan 2006 11:43:00 +0000
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Tue, 24 Jan 2006 11:45:28 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <44BDAFB888F59F408FAE3CC35AB4704102D877EB@orsmsx409>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <44BDAFB888F59F408FAE3CC35AB4704102D877EB@orsmsx409>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx

On 23 Jan 2006, at 21:13, King, Steven R wrote:

After trials and tribulations getting my serial ports in order, I'm
finally able to report on a Xen crash I've been seeing.

I have two domUs that share & map grant references with each other, then
both domUs crash.  Shortly thereafter, Xen crashes too.

With dead domUs, the grant references they once held are left orphaned.
Xen isn't provisioned to mop this up, hence the well placed
BUG(rd==NULL).  Make any sense?  I'd be over my head to submit a patch
for this, so I'm hoping for help.

Let's say domain A maps pages belonging to domain B (implying that B granted access to A).

If B crashes then the domain should stick around as a zombie until all mappings of its pages by other domains have gone away. This should mean that if A crashes or dies and calls gnttab_release_mappings(), it should not be possible for B to have disappeared at that point, and find_domain_by_id() should succeed.

Neither of your domains are running on shadow page tables, are they?

 -- Keir

Xen-devel mailing list