[PATCH 4.9 044/104] i40iw: Receive netdev events post INET_NOTIFIER state

[Greg Kroah-Hartman]

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

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

From: Shiraz Saleem <shiraz.saleem@xxxxxxxxx>


[ Upstream commit 871a8623d3b40221ad1103aff715dfee0aa4dacf ]

Netdev notification events are de-registered only when all
client iwdev instances are removed. If a single client is closed
and re-opened, netdev events could arrive even before the Control
Queue-Pair (CQP) is created, causing a NULL pointer dereference crash
in i40iw_get_cqp_request. Fix this by allowing netdev event
notification only after we have reached the INET_NOTIFIER state with
respect to device initialization.

Reported-by: Stefan Assmann <sassmann@xxxxxxxxxx>
Signed-off-by: Shiraz Saleem <shiraz.saleem@xxxxxxxxx>
Reviewed-by: Yuval Shaia <yuval.shaia@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/hw/i40iw/i40iw_utils.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/infiniband/hw/i40iw/i40iw_utils.c
+++ b/drivers/infiniband/hw/i40iw/i40iw_utils.c
@@ -159,6 +159,9 @@ int i40iw_inetaddr_event(struct notifier
 		return NOTIFY_DONE;
 
 	iwdev = &hdl->device;
+	if (iwdev->init_state < INET_NOTIFIER)
+		return NOTIFY_DONE;
+
 	netdev = iwdev->ldev->netdev;
 	upper_dev = netdev_master_upper_dev_get(netdev);
 	if (netdev != event_netdev)
@@ -231,6 +234,9 @@ int i40iw_inet6addr_event(struct notifie
 		return NOTIFY_DONE;
 
 	iwdev = &hdl->device;
+	if (iwdev->init_state < INET_NOTIFIER)
+		return NOTIFY_DONE;
+
 	netdev = iwdev->ldev->netdev;
 	if (netdev != event_netdev)
 		return NOTIFY_DONE;
@@ -280,6 +286,8 @@ int i40iw_net_event(struct notifier_bloc
 		if (!iwhdl)
 			return NOTIFY_DONE;
 		iwdev = &iwhdl->device;
+		if (iwdev->init_state < INET_NOTIFIER)
+			return NOTIFY_DONE;
 		p = (__be32 *)neigh->primary_key;
 		i40iw_copy_ip_ntohl(local_ipaddr, p);
 		if (neigh->nud_state & NUD_VALID) {