From: Robert Hancock <hancock@xxxxxxxxxxxxx> [ Upstream commit 6bb9e376c2a4cc5120c3bf5fd3048b9a0a6ec1f8 ] If some of the switch ports were not listed in the device tree, due to being unused, the ksz_mib_read_work function ended up accessing a NULL dp->slave pointer and causing an oops. Skip checking statistics for any unused ports. Fixes: 7c6ff470aa867f53 ("net: dsa: microchip: add MIB counter reading support") Signed-off-by: Robert Hancock <hancock@xxxxxxxxxxxxx> Reviewed-by: Vivien Didelot <vivien.didelot@xxxxxxxxx> Reviewed-by: Andrew Lunn <andrew@xxxxxxx> Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/dsa/microchip/ksz_common.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/net/dsa/microchip/ksz_common.c +++ b/drivers/net/dsa/microchip/ksz_common.c @@ -83,6 +83,9 @@ static void ksz_mib_read_work(struct wor int i; for (i = 0; i < dev->mib_port_cnt; i++) { + if (dsa_is_unused_port(dev->ds, i)) + continue; + p = &dev->ports[i]; mib = &p->mib; mutex_lock(&mib->cnt_mutex);