[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190628123659.139576-4-sgarzare@redhat.com>
Date: Fri, 28 Jun 2019 14:36:59 +0200
From: Stefano Garzarella <sgarzare@...hat.com>
To: netdev@...r.kernel.org
Cc: kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org,
Stefan Hajnoczi <stefanha@...hat.com>,
"Michael S. Tsirkin" <mst@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Jason Wang <jasowang@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/3] 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@...hat.com>
Signed-off-by: Stefano Garzarella <sgarzare@...hat.com>
---
net/vmw_vsock/virtio_transport.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index 1b44ec6f3f6c..96dafa978268 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -680,12 +680,6 @@ 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);
@@ -740,6 +734,15 @@ 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);
--
2.20.1
Powered by blists - more mailing lists