The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 246bbf2f977ea36aaf41f5d24370fef433250728 Mon Sep 17 00:00:00 2001
From: Sergei Antonov <saproj@xxxxxxxxx>
Date: Thu, 11 Aug 2022 10:09:39 +0300
Subject: [PATCH] net: dsa: mv88e6060: prevent crash on an unused port
If the port isn't a CPU port nor a user port, 'cpu_dp'
is a null pointer and a crash happened on dereferencing
it in mv88e6060_setup_port():
[ 9.575872] Unable to handle kernel NULL pointer dereference at virtual address 00000014
...
[ 9.942216] mv88e6060_setup from dsa_register_switch+0x814/0xe84
[ 9.948616] dsa_register_switch from mdio_probe+0x2c/0x54
[ 9.954433] mdio_probe from really_probe.part.0+0x98/0x2a0
[ 9.960375] really_probe.part.0 from driver_probe_device+0x30/0x10c
[ 9.967029] driver_probe_device from __device_attach_driver+0xb8/0x13c
[ 9.973946] __device_attach_driver from bus_for_each_drv+0x90/0xe0
[ 9.980509] bus_for_each_drv from __device_attach+0x110/0x184
[ 9.986632] __device_attach from bus_probe_device+0x8c/0x94
[ 9.992577] bus_probe_device from deferred_probe_work_func+0x78/0xa8
[ 9.999311] deferred_probe_work_func from process_one_work+0x290/0x73c
[ 10.006292] process_one_work from worker_thread+0x30/0x4b8
[ 10.012155] worker_thread from kthread+0xd4/0x10c
[ 10.017238] kthread from ret_from_fork+0x14/0x3c
Fixes: 0abfd494deef ("net: dsa: use dedicated CPU port")
CC: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx>
CC: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: Sergei Antonov <saproj@xxxxxxxxx>
Signed-off-by: Vladimir Oltean <olteanv@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220811070939.1717146-1-saproj@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
diff --git a/drivers/net/dsa/mv88e6060.c b/drivers/net/dsa/mv88e6060.c
index a4c6eb9a52d0..83dca9179aa0 100644
--- a/drivers/net/dsa/mv88e6060.c
+++ b/drivers/net/dsa/mv88e6060.c
@@ -118,6 +118,9 @@ static int mv88e6060_setup_port(struct mv88e6060_priv *priv, int p)
int addr = REG_PORT(p);
int ret;
+ if (dsa_is_unused_port(priv->ds, p))
+ return 0;
+
/* Do not force flow control, disable Ingress and Egress
* Header tagging, disable VLAN tunneling, and set the port
* state to Forwarding. Additionally, if this is the CPU
