vsock/virtio: fix kernel panic after device hot-unplug

[ Upstream commit 22b5c0b63f32568e130fa2df4ba23efce3eb495b ]

virtio_vsock_remove() invokes the vsock_core_exit() also if there
are opened sockets for the AF_VSOCK protocol family. In this way
the vsock "transport" pointer is set to NULL, triggering the
kernel panic at the first socket activity.

This patch move the vsock_core_init()/vsock_core_exit() in the
virtio_vsock respectively in module_init and module_exit functions,
that cannot be invoked until there are open sockets.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1609699
Reported-by: Yan Fu <yafu@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 936d7eee62d03efbac1e278272ca8fd917a40622..6cbc08d82e7fdd3e053fef25b57f66e4abe2d6aa 100644 (file)
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -71,6 +71,9 @@ static u32 virtio_transport_get_local_cid(void)
 {
        struct virtio_vsock *vsock = virtio_vsock_get();
 
+       if (!vsock)
+               return VMADDR_CID_ANY;
+
        return vsock->guest_cid;
 }
 
@@ -495,10 +498,6 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 
        virtio_vsock_update_guest_cid(vsock);
 
-       ret = vsock_core_init(&virtio_transport.transport);
-       if (ret < 0)
-               goto out_vqs;
-
        vsock->rx_buf_nr = 0;
        vsock->rx_buf_max_nr = 0;
        atomic_set(&vsock->queued_replies, 0);
@@ -526,8 +525,6 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
        mutex_unlock(&the_virtio_vsock_mutex);
        return 0;
 
-out_vqs:
-       vsock->vdev->config->del_vqs(vsock->vdev);
 out:
        kfree(vsock);
        mutex_unlock(&the_virtio_vsock_mutex);
@@ -567,7 +564,6 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
 
        mutex_lock(&the_virtio_vsock_mutex);
        the_virtio_vsock = NULL;
-       vsock_core_exit();
        mutex_unlock(&the_virtio_vsock_mutex);
 
        vdev->config->del_vqs(vdev);
@@ -600,14 +596,28 @@ static int __init virtio_vsock_init(void)
        virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0);
        if (!virtio_vsock_workqueue)
                return -ENOMEM;
+
        ret = register_virtio_driver(&virtio_vsock_driver);
        if (ret)
-               destroy_workqueue(virtio_vsock_workqueue);
+               goto out_wq;
+
+       ret = vsock_core_init(&virtio_transport.transport);
+       if (ret)
+               goto out_vdr;
+
+       return 0;
+
+out_vdr:
+       unregister_virtio_driver(&virtio_vsock_driver);
+out_wq:
+       destroy_workqueue(virtio_vsock_workqueue);
        return ret;
+
 }
 
 static void __exit virtio_vsock_exit(void)
 {
+       vsock_core_exit();
        unregister_virtio_driver(&virtio_vsock_driver);
        destroy_workqueue(virtio_vsock_workqueue);
 }