From e84e7a56a3aa2963db506299e29a5f3f09377f9b Mon Sep 17 00:00:00 2001 From: Amit Shah Date: Fri, 8 Mar 2013 11:30:18 +1100 Subject: [PATCH] virtio: rng: disallow multiple device registrations, fixes crashes 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 Reported-by: Signed-off-by: Amit Shah Signed-off-by: Rusty Russell Cc: stable@kernel.org --- drivers/char/hw_random/virtio-rng.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index 10fd71ccf587..6bf4d47324eb 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -92,14 +92,22 @@ static int probe_common(struct virtio_device *vdev) { 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; } @@ -112,6 +120,7 @@ static void remove_common(struct virtio_device *vdev) busy = false; hwrng_unregister(&virtio_hwrng); vdev->config->del_vqs(vdev); + vq = NULL; } static int virtrng_probe(struct virtio_device *vdev)