[PATCH 4.9 72/96] vsock/virtio: fix kernel panic after device hot-unplug

Greg Kroah-Hartman
2019-03-12T17:18:36Z

[ 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>
---
net/vmw_vsock/virtio_transport.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 936d7eee62d0..6cbc08d82e7f 100644
--- 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);
}
--
2.19.1