[PATCH net v3] virtio_net: fix virtnet_open and virtnet_probe competing for try_fill_recv

* [PATCH net v3] virtio_net: fix virtnet_open and virtnet_probe competing for try_fill_recv
@ 2016-05-31  3:52 Yunjian Wang
  2016-05-31 21:22 ` David Miller
  0 siblings, 1 reply; 2+ messages in thread
From: Yunjian Wang @ 2016-05-31  3:52 UTC (permalink / raw)
  To: davem, jasowang, mst, rusty, netdev; +Cc: liuyongan, Yunjian Wang

In function virtnet_open() and virtnet_probe(), func try_fill_recv() may
be executed at the same time. VQ in virtqueue_add() has not been protected
well and BUG_ON will be triggered when virito_net.ko being removed.

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/net/virtio_net.c | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 49d84e5..e0638e5 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1925,24 +1925,11 @@ static int virtnet_probe(struct virtio_device *vdev)
 
 	virtio_device_ready(vdev);
 
-	/* Last of all, set up some receive buffers. */
-	for (i = 0; i < vi->curr_queue_pairs; i++) {
-		try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);
-
-		/* If we didn't even get one input buffer, we're useless. */
-		if (vi->rq[i].vq->num_free ==
-		    virtqueue_get_vring_size(vi->rq[i].vq)) {
-			free_unused_bufs(vi);
-			err = -ENOMEM;
-			goto free_recv_bufs;
-		}
-	}
-
 	vi->nb.notifier_call = &virtnet_cpu_callback;
 	err = register_hotcpu_notifier(&vi->nb);
 	if (err) {
 		pr_debug("virtio_net: registering cpu notifier failed\n");
-		goto free_recv_bufs;
+		goto free_unregister_netdev;
 	}
 
 	/* Assume link up if device can't report link status,
@@ -1960,10 +1947,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 
 	return 0;
 
-free_recv_bufs:
+free_unregister_netdev:
 	vi->vdev->config->reset(vdev);
 
-	free_receive_bufs(vi);
 	unregister_netdev(dev);
 free_vqs:
 	cancel_delayed_work_sync(&vi->refill);
-- 
1.7.12.4

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