Re: [Xen-devel] Backend in user space, how is its kernel dev unregistered?

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 05/03/2009 12:40, "Markus Armbruster" <armbru@xxxxxxxxxx> wrote:

> Let me elaborate.
> 
> Backend device registration is split between xenbus_probe.c
> (registering) and the backend device driver (unregistering).  When a
> device node shows up in xenstore, xenbus_probe_node() calls
> device_register().  When the backend driver sees the frontend shut down,
> it calls device_unregister().  For an example see frontend_changed() in
> drivers/xen/blkback/xenbus.c.
> 
> The vfb and vkbd backends live in user space, i.e. there is no backend
> driver in the kernel.  device_unregister() never gets called.  This is a
> resource leak.
> 
> Does this explain the problem sufficienctly?

Ah yes, I think that makes sense. Does xenbus_probe really do a
device_register() despite not finding a backend kernel driver to handles the
device? That would sound like the source of the problem, to me.

 -- Keir



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