This is a note to let you know that I've just added the patch titled
netvsc: add rcu_read locking to netvsc callback
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netvsc-add-rcu_read-locking-to-netvsc-callback.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Feb 1 08:50:24 CET 2017
From: stephen hemminger <stephen@xxxxxxxxxxxxxxxxxx>
Date: Wed, 11 Jan 2017 09:16:32 -0800
Subject: netvsc: add rcu_read locking to netvsc callback
From: stephen hemminger <stephen@xxxxxxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/hyperv/netvsc_drv.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -659,6 +659,7 @@ int netvsc_recv_callback(struct hv_devic
* 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_devic
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_devic
* TODO - use NAPI?
*/
netif_rx(skb);
+ rcu_read_unlock();
return 0;
}
Patches currently in stable-queue which might be from stephen@xxxxxxxxxxxxxxxxxx are
queue-4.9/netvsc-add-rcu_read-locking-to-netvsc-callback.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html