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authorstephen hemminger <stephen@networkplumber.org>2017-01-11 09:16:32 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-02-04 09:47:08 +0100
commit5b3df4401064ef94cddac976aba1474a7050fa5e (patch)
treedbb347ccc3ff3c55b338f465a95e9713f562d78a /drivers
parenta37f2311e63c8989675e297cdc9300cbec6e2217 (diff)
netvsc: add rcu_read locking to netvsc callback
[ Upstream commit 0719e72ccb801829a3d735d187ca8417f0930459 ] 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: f207c10d9823 ("hv_netvsc: use RCU to protect vf_netdev") Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/hyperv/netvsc_drv.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index c9140c3aeb67..ff038e507fd6 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -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;
}