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authorStefano Garzarella <sgarzare@redhat.com>2019-07-05 14:04:54 +0300
committerDavid S. Miller <davem@davemloft.net>2019-07-09 01:35:17 +0300
commite226121fcc26e69c721a435aa9348a2f452e4d3e (patch)
tree0ef74aa77ece3c192dfef9cf8a251e12ddf8a63d /net/vmw_vsock/virtio_transport.c
parentb917507e5ad983085d29069369778b16aa03a0a8 (diff)
downloadlinux-e226121fcc26e69c721a435aa9348a2f452e4d3e.tar.xz
vsock/virtio: fix flush of works during the .remove()
This patch moves the flush of works after vdev->config->del_vqs(vdev), because we need to be sure that no workers run before to free the 'vsock' object. Since we stopped the workers using the [tx|rx|event]_run flags, we are sure no one is accessing the device while we are calling vdev->config->reset(vdev), so we can safely move the workers' flush. Before the vdev->config->del_vqs(vdev), workers can be scheduled by VQ callbacks, so we must flush them after del_vqs(), to avoid use-after-free of 'vsock' object. Suggested-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/vmw_vsock/virtio_transport.c')
-rw-r--r--net/vmw_vsock/virtio_transport.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 4dbdce7746bd..0815d1357861 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -681,12 +681,6 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
rcu_assign_pointer(the_virtio_vsock, NULL);
synchronize_rcu();
- flush_work(&vsock->loopback_work);
- flush_work(&vsock->rx_work);
- flush_work(&vsock->tx_work);
- flush_work(&vsock->event_work);
- flush_work(&vsock->send_pkt_work);
-
/* Reset all connected sockets when the device disappear */
vsock_for_each_connected_socket(virtio_vsock_reset_sock);
@@ -741,6 +735,15 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
/* Delete virtqueues and flush outstanding callbacks if any */
vdev->config->del_vqs(vdev);
+ /* Other works can be queued before 'config->del_vqs()', so we flush
+ * all works before to free the vsock object to avoid use after free.
+ */
+ flush_work(&vsock->loopback_work);
+ flush_work(&vsock->rx_work);
+ flush_work(&vsock->tx_work);
+ flush_work(&vsock->event_work);
+ flush_work(&vsock->send_pkt_work);
+
mutex_unlock(&the_virtio_vsock_mutex);
kfree(vsock);