From 765bda93d043c7c0c15305a916e0fa553fdd9964 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 31 Mar 2020 15:17:36 +0100 Subject: [PATCH] net: dsa: fix oops while probing Marvell DSA switches Fix an oops in dsa_port_phylink_mac_change() caused by a combination of a20f997010c4 ("net: dsa: Don't instantiate phylink for CPU/DSA ports unless needed") and the net-dsa-improve-serdes-integration series of patches 65b7a2c8e369 ("Merge branch 'net-dsa-improve-serdes-integration'"). Unable to handle kernel NULL pointer dereference at virtual address 00000124 pgd = c0004000 [00000124] *pgd=00000000 Internal error: Oops: 805 [#1] SMP ARM Modules linked in: tag_edsa spi_nor mtd xhci_plat_hcd mv88e6xxx(+) xhci_hcd armada_thermal marvell_cesa dsa_core ehci_orion libdes phy_armada38x_comphy at24 mcp3021 sfp evbug spi_orion sff mdio_i2c CPU: 1 PID: 214 Comm: irq/55-mv88e6xx Not tainted 5.6.0+ #470 Hardware name: Marvell Armada 380/385 (Device Tree) PC is at phylink_mac_change+0x10/0x88 LR is at mv88e6352_serdes_irq_status+0x74/0x94 [mv88e6xxx] Signed-off-by: Russell King Reviewed-by: Vivien Didelot Signed-off-by: David S. Miller --- net/dsa/slave.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/dsa/slave.c b/net/dsa/slave.c index 9692a726f2ed..5390ff541658 100644 --- a/net/dsa/slave.c +++ b/net/dsa/slave.c @@ -1585,7 +1585,8 @@ void dsa_port_phylink_mac_change(struct dsa_switch *ds, int port, bool up) { const struct dsa_port *dp = dsa_to_port(ds, port); - phylink_mac_change(dp->pl, up); + if (dp->pl) + phylink_mac_change(dp->pl, up); } EXPORT_SYMBOL_GPL(dsa_port_phylink_mac_change);