From 4d15a73de3f69be77cc9ffc26806ef67df091342 Mon Sep 17 00:00:00 2001
From: Amit Cohen <amcohen@nvidia.com>
Date: Tue, 23 Nov 2021 09:52:56 +0200
Subject: [PATCH 6/7] mlxsw: spectrum: Protect driver from buggy firmware
Git-commit: 63b08b1f6834bbb0b4f7783bf63b80c8c8e9a047
Patch-mainline: v5.16-rc3
References: git-fixes
When processing port up/down events generated by the device's firmware,
the driver protects itself from events reported for non-existent local
ports, but not the CPU port (local port 0), which exists, but lacks a
netdev.
This can result in a NULL pointer dereference when calling
netif_carrier_{on,off}().
Fix this by bailing early when processing an event reported for the CPU
port. Problem was only observed when running on top of a buggy emulator.
Fixes: 28b1987ef506 ("mlxsw: spectrum: Register CPU port with devlink")
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 8dcc489e5329..93b02fb113cb 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -2093,7 +2093,7 @@ static void mlxsw_sp_pude_event_func(const struct mlxsw_reg_info *reg,
max_ports = mlxsw_core_max_ports(mlxsw_sp->core);
local_port = mlxsw_reg_pude_local_port_get(pude_pl);
- if (WARN_ON_ONCE(local_port >= max_ports))
+ if (WARN_ON_ONCE(!local_port || local_port >= max_ports))
return;
mlxsw_sp_port = mlxsw_sp->ports[local_port];
if (!mlxsw_sp_port)
--
2.16.4