From: Florian Fainelli <f.fainelli@xxxxxxxxx>
[ Upstream commit 050569fc8384c8056bacefcc246bcb2dfe574936 ]
When ndo_get_phys_port_name() for the CPU port was added we introduced
an early check for when the DSA master network device in
dsa_master_ndo_setup() already implements ndo_get_phys_port_name(). When
we perform the teardown operation in dsa_master_ndo_teardown() we would
not be checking that cpu_dp->orig_ndo_ops was successfully allocated and
non-NULL initialized.
With network device drivers such as virtio_net, this leads to a NPD as
soon as the DSA switch hanging off of it gets torn down because we are
now assigning the virtio_net device's netdev_ops a NULL pointer.
Fixes: da7b9e9b00d4 ("net: dsa: Add ndo_get_phys_port_name() for CPU port")
Reported-by: Allen Pais <allen.pais@xxxxxxxxxx>
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Tested-by: Allen Pais <allen.pais@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/dsa/master.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -289,7 +289,8 @@ static void dsa_master_ndo_teardown(stru
{
struct dsa_port *cpu_dp = dev->dsa_ptr;
- dev->netdev_ops = cpu_dp->orig_ndo_ops;
+ if (cpu_dp->orig_ndo_ops)
+ dev->netdev_ops = cpu_dp->orig_ndo_ops;
cpu_dp->orig_ndo_ops = NULL;
}
