Re: [Xen-devel] Fwd: NetBSD xl core-dump not working... Memory fault (core dumped)

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2013-11-12 at 10:48 +0100, Roger Pau Monnà wrote:
> > vaddr is certainly not NULL, it's checked right before. It could be
> > non-NULL and still invalid if xc_map_foreign_range were buggy on NetBSD,
> > but that is surely used elsewhere? I suppose it might have mapped an MFN
> > which was either invalid (or became invalid, but your bug is
> > deterministic, right?. IIRC NetBSD's privcmd foreign mappings are
> > populated lazily and not immediately like on Linux? If that were the
> > case (and I'm only vaguely aware of how NetBSD operates) then it would
> > be plausible that xc_map_foreign_range would succeed but that a
> > subsequent attempt to access the region would fault?
> 
> Yes, NetBSD privcmd maps the region lazily (it does the actual map on
> the page fault handler for that region).

Thanks for the confirmation. Would it be expected that a message would
be logged to dom0's dmesg if something went wrong here?

>  I have not tested it, but could
> you give a try to the following patch:
> 
> http://mail-index.netbsd.org/port-xen/2012/06/27/msg007464.html
> 
> It's quite old, but I expect there hasn't been many changes in NetBSD
> privcmd recently.
> 
> Roger.
> 



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