Virtualization - Feb 2010 - [PATCH] virtio: fix balloon without VIRTIO_BALLOON_F_STATS_VQ

When running under qemu-kvm-0.11.0:

	BUG: unable to handle kernel paging request at 56e58955
	...
	Process vballoon (pid: 1297, ti=c7976000 task=c70a6ca0 task.ti=c7
	...
	Call Trace:
	 [<c88253a3>] ? balloon+0x1b3/0x440 [virtio_balloon]
	 [<c041c2d7>] ? schedule+0x327/0x9d0
	 [<c88251f0>] ? balloon+0x0/0x440 [virtio_balloon]
	 [<c014a2d4>] ? kthread+0x74/0x80
	 [<c014a260>] ? kthread+0x0/0x80
	 [<c0103b36>] ? kernel_thread_helper+0x6/0x30

need_stats_update should be zero-initialized.

Signed-off-by: Rusty Russell <rusty at rustcorp.com.au>
Cc: Adam Litke <agl at us.ibm.com>

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -292,6 +292,7 @@ static int virtballoon_probe(struct virt
 	vb->num_pages = 0;
 	init_waitqueue_head(&vb->config_change);
 	vb->vdev = vdev;
+	vb->need_stats_update = 0;
 
 	/* We expect two virtqueues: inflate and deflate,
 	 * and optionally stat. */

On Mon, 2010-02-08 at 21:02 +1030, Rusty Russell wrote:
> need_stats_update should be zero-initialized.
Yes indeed.
Acked-by: Adam Litke <agl at us.ibm.com>
> Signed-off-by: Rusty Russell <rusty at rustcorp.com.au>
> Cc: Adam Litke <agl at us.ibm.com>
> 
> diff --git a/drivers/virtio/virtio_balloon.c
b/drivers/virtio/virtio_balloon.c
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -292,6 +292,7 @@ static int virtballoon_probe(struct virt
>  	vb->num_pages = 0;
>  	init_waitqueue_head(&vb->config_change);
>  	vb->vdev = vdev;
> +	vb->need_stats_update = 0;
> 
>  	/* We expect two virtqueues: inflate and deflate,
>  	 * and optionally stat. */

-- 
Thanks,
Adam