Re: [Xen-devel] [PATCH 26/38] xen: xenbus: add missing put_device call

Ian Campbell
2014-01-06T10:00:50Z

On Thu, 2014-01-02 at 13:53 +0000, David Vrabel wrote:
> On 19/12/13 15:03, Levente Kurusa wrote:
> > This is required so that we give up the last reference to the device.
> >
> > Signed-off-by: Levente Kurusa <levex@linux.com>
> > ---
> > drivers/xen/xenbus/xenbus_probe.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
> > index 3c0a74b..4abb9ee 100644
> > --- a/drivers/xen/xenbus/xenbus_probe.c
> > +++ b/drivers/xen/xenbus/xenbus_probe.c
> > @@ -465,8 +465,10 @@ int xenbus_probe_node(struct xen_bus_type *bus,
> >
> > /* Register with generic device framework. */
> > err = device_register(&xendev->dev);
> > - if (err)
> > + if (err) {
> > + put_device(&xendev->dev);
> > goto fail;
> > + }
> >
> > return 0;
> > fail:
>
> There is a kfree(xendev) here so this introduces a double-free.

How? put_device doesn't touch xendev itself, does it? It just drops the
ref on the dev member which is not separately dynamically allocated and
so not freed either.

Ian.