Commit 5b3df440 authored by stephen hemminger's avatar stephen hemminger Committed by Greg Kroah-Hartman

netvsc: add rcu_read locking to netvsc callback

[ Upstream commit 0719e72c ]

The receive callback (in tasklet context) is using RCU to get reference
to associated VF network device but this is not safe. RCU read lock
needs to be held. Found by running with full lockdep debugging
enabled.

Fixes: f207c10d ("hv_netvsc: use RCU to protect vf_netdev")
Signed-off-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a37f2311
......@@ -659,6 +659,7 @@ int netvsc_recv_callback(struct hv_device *device_obj,
* policy filters on the host). Deliver these via the VF
* interface in the guest.
*/
rcu_read_lock();
vf_netdev = rcu_dereference(net_device_ctx->vf_netdev);
if (vf_netdev && (vf_netdev->flags & IFF_UP))
net = vf_netdev;
......@@ -667,6 +668,7 @@ int netvsc_recv_callback(struct hv_device *device_obj,
skb = netvsc_alloc_recv_skb(net, packet, csum_info, *data, vlan_tci);
if (unlikely(!skb)) {
++net->stats.rx_dropped;
rcu_read_unlock();
return NVSP_STAT_FAIL;
}
......@@ -696,6 +698,7 @@ int netvsc_recv_callback(struct hv_device *device_obj,
* TODO - use NAPI?
*/
netif_rx(skb);
rcu_read_unlock();
return 0;
}
......
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