[PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized

[Jason Wang]

The code will try to access dev->iotlb when processing
VHOST_IOTLB_INVALIDATE even if it was not initialized which may lead
to NULL pointer dereference. Fixes this by check dev->iotlb before.

Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 drivers/vhost/vhost.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 549771a..5727b18 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1015,6 +1015,10 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
                vhost_iotlb_notify_vq(dev, msg);
                break;
        case VHOST_IOTLB_INVALIDATE:
+               if (!dev->iotlb) {
+                       ret = -EFAULT;
+                       break;
+               }
                vhost_vq_meta_reset(dev);
                vhost_del_umem_range(dev->iotlb, msg->iova,
                                     msg->iova + msg->size - 1);
-- 
2.7.4