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authorMichael S. Tsirkin <mst@redhat.com>2009-10-28 04:03:38 -0700
committerDavid S. Miller <davem@davemloft.net>2009-10-28 04:03:38 -0700
commit03f191bab77c0148e458dbbd0a37241be2a2faf9 (patch)
tree9cdee187b2e64d2535e2c1192c68fd77e925c06b
parent345056af41feeda506a8993474b9cbb2c66bc9fb (diff)
downloadvexpress-lsk-03f191bab77c0148e458dbbd0a37241be2a2faf9.tar.gz
virtio-net: fix data corruption with OOM
virtio net used to unlink skbs from send queues on error, but ever since 48925e372f04f5e35fec6269127c62b2c71ab794 we do not do this. This causes guest data corruption and crashes with vhost since net core can requeue the skb or free it without it being taken off the list. This patch fixes this by queueing the skb after successful transmit. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/virtio_net.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 54bf0912b73..d9ebac8a2d9 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -517,8 +517,7 @@ again:
/* Free up any pending old buffers before queueing new ones. */
free_old_xmit_skbs(vi);
- /* Put new one in send queue and do transmit */
- __skb_queue_head(&vi->send, skb);
+ /* Try to transmit */
capacity = xmit_skb(vi, skb);
/* This can happen with OOM and indirect buffers. */
@@ -532,8 +531,17 @@ again:
}
return NETDEV_TX_BUSY;
}
-
vi->svq->vq_ops->kick(vi->svq);
+
+ /*
+ * Put new one in send queue. You'd expect we'd need this before
+ * xmit_skb calls add_buf(), since the callback can be triggered
+ * immediately after that. But since the callback just triggers
+ * another call back here, normal network xmit locking prevents the
+ * race.
+ */
+ __skb_queue_head(&vi->send, skb);
+
/* Don't wait up for transmitted skbs to be freed. */
skb_orphan(skb);
nf_reset(skb);