net: dsa: don't call switchdev_bridge_port_unoffload for unoffloaded bridge ports

For ports that have a NULL dp->bridge_dev, dsa_port_to_bridge_port()
also returns NULL as expected.

Issue #1 is that we are performing a NULL pointer dereference on brport_dev.

Issue #2 is that these are ports on which switchdev_bridge_port_offload
has not been called, so we should not call switchdev_bridge_port_unoffload
on them either.

Both issues are addressed by checking against a NULL brport_dev in
dsa_port_pre_bridge_leave and exiting early.

Fixes: 2f5dc00f7a3e ("net: bridge: switchdev: let drivers inform which bridge ports are offloaded")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dsa/port.c b/net/dsa/port.c
index 4fbe81f..3b775d7 100644 (file)
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -373,6 +373,10 @@ void dsa_port_pre_bridge_leave(struct dsa_port *dp, struct net_device *br)
 {
        struct net_device *brport_dev = dsa_port_to_bridge_port(dp);
 
+       /* Don't try to unoffload something that is not offloaded */
+       if (!brport_dev)
+               return;
+
        switchdev_bridge_port_unoffload(brport_dev, dp,
                                        &dsa_slave_switchdev_notifier,
                                        &dsa_slave_switchdev_blocking_notifier);