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@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 246bbf2f977ea36aaf41f5d24370fef433250728 Mon Sep 17 00:00:00 2001 From: Sergei Antonov saproj@gmail.com 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@savoirfairelinux.com CC: Florian Fainelli f.fainelli@gmail.com Signed-off-by: Sergei Antonov saproj@gmail.com Signed-off-by: Vladimir Oltean olteanv@gmail.com Link: https://lore.kernel.org/r/20220811070939.1717146-1-saproj@gmail.com Signed-off-by: Jakub Kicinski kuba@kernel.org
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