[ 03/48] virtio: rng: disallow multiple device registrations, fixes crashes

From: Greg Kroah-Hartman
Date: Mon Mar 18 2013 - 17:44:24 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Amit Shah <amit.shah@xxxxxxxxxx>

commit e84e7a56a3aa2963db506299e29a5f3f09377f9b upstream.

The code currently only supports one virtio-rng device at a time.
Invoking guests with multiple devices causes the guest to blow up.

Check if we've already registered and initialised the driver. Also
cleanup in case of registration errors or hot-unplug so that a new
device can be used.

Reported-by: Peter Krempa <pkrempa@xxxxxxxxxx>
Reported-by: <yunzheng@xxxxxxxxxx>
Signed-off-by: Amit Shah <amit.shah@xxxxxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/char/hw_random/virtio-rng.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -89,14 +89,22 @@ static int virtrng_probe(struct virtio_d
{
int err;

+ if (vq) {
+ /* We only support one device for now */
+ return -EBUSY;
+ }
/* We expect a single virtqueue. */
vq = virtio_find_single_vq(vdev, random_recv_done, "input");
- if (IS_ERR(vq))
- return PTR_ERR(vq);
+ if (IS_ERR(vq)) {
+ err = PTR_ERR(vq);
+ vq = NULL;
+ return err;
+ }

err = hwrng_register(&virtio_hwrng);
if (err) {
vdev->config->del_vqs(vdev);
+ vq = NULL;
return err;
}

@@ -108,6 +116,7 @@ static void __devexit virtrng_remove(str
vdev->config->reset(vdev);
hwrng_unregister(&virtio_hwrng);
vdev->config->del_vqs(vdev);
+ vq = NULL;
}

static struct virtio_device_id id_table[] = {


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/