[PATCH][next] mlxsw: thermal: Fix null dereference of NULL temperature parameter

From: Colin King
Date: Wed Jun 09 2021 - 13:58:02 EST

From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The call to mlxsw_thermal_module_temp_and_thresholds_get passes a NULL
pointer for the temperature and this can be dereferenced in this function
if the mlxsw_reg_query call fails. The simplist fix is to pass the
address of dummy temperature variable instead of a NULL pointer.

Addresses-Coverity: ("Explicit null dereferenced")
Fixes: 72a64c2fe9d8 ("mlxsw: thermal: Read module temperature thresholds using MTMP register")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
drivers/net/ethernet/mellanox/mlxsw/core_thermal.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
index d54b67d0bda7..0998dcc9cac0 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
@@ -743,7 +743,7 @@ mlxsw_thermal_module_init(struct device *dev, struct mlxsw_core *core,
struct mlxsw_thermal *thermal, u8 module)
struct mlxsw_thermal_module *module_tz;
- int crit_temp, emerg_temp;
+ int dummy_temp, crit_temp, emerg_temp;
u16 sensor_index;

sensor_index = MLXSW_REG_MTMP_MODULE_INDEX_MIN + module;
@@ -758,7 +758,7 @@ mlxsw_thermal_module_init(struct device *dev, struct mlxsw_core *core,
/* Initialize all trip point. */
/* Read module temperature and thresholds. */
- mlxsw_thermal_module_temp_and_thresholds_get(core, sensor_index, NULL,
+ mlxsw_thermal_module_temp_and_thresholds_get(core, sensor_index, &dummy_temp,
&crit_temp, &emerg_temp);
/* Update trip point according to the module data. */
return mlxsw_thermal_module_trips_update(dev, core, module_tz,