Re: [PATCH] virtio_balloon: set DRIVER_OK before using device

[Michael S. Tsirkin]

On Thu, Mar 05, 2015 at 01:24:47PM +1030, Rusty Russell wrote:
> "Michael S. Tsirkin" <mst@xxxxxxxxxx> writes:
> > virtio spec requires that all drivers set DRIVER_OK
> > before using devices. While balloon isn't yet
> > included in the virtio 1 spec, previous spec versions
> > also required this.
> >
> > virtio balloon might violate this rule: probe calls
> > kthread_run before setting DRIVER_OK, which might run
> > immediately and cause balloon to inflate/deflate.
> >
> > To fix, call virtio_device_ready before running the kthread.
> >
> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> 
> Replied, CC'd stable.

Did you mean applied?

> Thanks,
> Rusty.
> 
> 
> > ---
> >  drivers/virtio/virtio_balloon.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> > index 5a6ad6d..6a356e3 100644
> > --- a/drivers/virtio/virtio_balloon.c
> > +++ b/drivers/virtio/virtio_balloon.c
> > @@ -508,6 +508,8 @@ static int virtballoon_probe(struct virtio_device *vdev)
> >  	if (err < 0)
> >  		goto out_oom_notify;
> >  
> > +	virtio_device_ready(vdev);
> > +
> >  	vb->thread = kthread_run(balloon, vb, "vballoon");
> >  	if (IS_ERR(vb->thread)) {
> >  		err = PTR_ERR(vb->thread);
> > -- 
> > MST
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