[PATCH 4.4 17/50] IB/ipoib: rtnl_unlock can not come after free_netdev

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Feras Daoud <ferasda@xxxxxxxxxxxx>


[ Upstream commit 89a3987ab7a923c047c6dec008e60ad6f41fac22 ]

The ipoib_vlan_add function calls rtnl_unlock after free_netdev,
rtnl_unlock not only releases the lock, but also calls netdev_run_todo.
The latter function browses the net_todo_list array and completes the
unregistration of all its net_device instances. If we call free_netdev
before rtnl_unlock, then netdev_run_todo call over the freed device causes
panic.
To fix, move rtnl_unlock call before free_netdev call.

Fixes: 9baa0b036410 ("IB/ipoib: Add rtnl_link_ops support")
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: Feras Daoud <ferasda@xxxxxxxxxxxx>
Signed-off-by: Erez Shitrit <erezsh@xxxxxxxxxxxx>
Reviewed-by: Yuval Shaia <yuval.shaia@xxxxxxxxxx>
Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/infiniband/ulp/ipoib/ipoib_vlan.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_vlan.c
@@ -160,11 +160,11 @@ int ipoib_vlan_add(struct net_device *pd
 out:
 	up_write(&ppriv->vlan_rwsem);
 
+	rtnl_unlock();
+
 	if (result)
 		free_netdev(priv->dev);
 
-	rtnl_unlock();
-
 	return result;
 }