[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] Xen crashing when killing a domain with no VCPUs allocated

On 07/18/2014 05:39 PM, Ian Campbell wrote:
On Fri, 2014-07-18 at 14:27 +0100, Julien Grall wrote:
Hi all,

I've been played with the function alloc_vcpu on ARM. And I hit one case
where this function can failed.

During domain creation, the toolstack will call DOMCTL_max_vcpus which may
fail, for instance because alloc_vcpu didn't succeed. In this case, the
toolstack will call DOMCTL_domaindestroy. And I got the below stack trace.

It can be reproduced on Xen 4.5 (and I also suspect Xen 4.4) by returning
in an error in vcpu_initialize.

I'm not sure how to correctly fix it.
I think a simple check at the head of the function would be ok.

Alternatively perhaps in sched_mode_domain, which could either detect
this or could detect a domain in pool0 being moved to pool0 and short

(XEN)    [<00226870>] sched_move_domain+0x3cc/0x42c
(XEN)    [<0020925c>] domain_kill+0xc8/0x178
This call path surprised me but it is from:

commit bac6334b51d9bcfe57ecf4a4cb5288348fcf044a
Author: Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>
Date:   Tue May 20 15:55:42 2014 +0200

     move domain to cpupool0 before destroying it

And this is the second unforseen hypervisor crash that happened as a side effect of this patch. Obviously I need to be more of a bastard as a mainainer.


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.