KVM: use after free in kvm_ioctl_create_device()

commit a0f1d21c upstream.

We should move the ops->destroy(dev) after the list_del(&dev->vm_node)
so that we don't use "dev" after freeing it.

Fixes: a28ebea2 ("KVM: Protect device ops->create and list_add with kvm->lock")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

virt/kvm/kvm_main.c

@@ -2852,10 +2852,10 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
 
 	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
 	if (ret < 0) {
-		ops->destroy(dev);
 		mutex_lock(&kvm->lock);
 		list_del(&dev->vm_node);
 		mutex_unlock(&kvm->lock);
+		ops->destroy(dev);
 		return ret;
 	}