thermal: of: fix double-free on unregistration

Since commit 3d439b1a2ad3 ("thermal/core: Alloc-copy-free the thermal
zone parameters structure"), thermal_zone_device_register() allocates
a copy of the tzp argument and frees it when unregistering, so
thermal_of_zone_register() now ends up leaking its original tzp and
double-freeing the tzp copy. Fix this by locating tzp on stack instead.

Fixes: 3d439b1a2ad3 ("thermal/core: Alloc-copy-free the thermal zone parameters structure")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: 6.4+ <stable@vger.kernel.org> # 6.4+: 8bcbb18c61d6: thermal: core: constify params in thermal_zone_device_register
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
index 6fb14e5..bc07ae1 100644 (file)
--- a/drivers/thermal/thermal_of.c
+++ b/drivers/thermal/thermal_of.c
@@ -238,17 +238,13 @@ static int thermal_of_monitor_init(struct device_node *np, int *delay, int *pdel
        return 0;
 }
 
-static struct thermal_zone_params *thermal_of_parameters_init(struct device_node *np)
+static void thermal_of_parameters_init(struct device_node *np,
+                                      struct thermal_zone_params *tzp)
 {
-       struct thermal_zone_params *tzp;
        int coef[2];
        int ncoef = ARRAY_SIZE(coef);
        int prop, ret;
 
-       tzp = kzalloc(sizeof(*tzp), GFP_KERNEL);
-       if (!tzp)
-               return ERR_PTR(-ENOMEM);
-
        tzp->no_hwmon = true;
 
        if (!of_property_read_u32(np, "sustainable-power", &prop))
@@ -267,8 +263,6 @@ static struct thermal_zone_params *thermal_of_parameters_init(struct device_node
 
        tzp->slope = coef[0];
        tzp->offset = coef[1];
-
-       return tzp;
 }
 
 static struct device_node *thermal_of_zone_get_by_name(struct thermal_zone_device *tz)
@@ -442,13 +436,11 @@ static int thermal_of_unbind(struct thermal_zone_device *tz,
 static void thermal_of_zone_unregister(struct thermal_zone_device *tz)
 {
        struct thermal_trip *trips = tz->trips;
-       struct thermal_zone_params *tzp = tz->tzp;
        struct thermal_zone_device_ops *ops = tz->ops;
 
        thermal_zone_device_disable(tz);
        thermal_zone_device_unregister(tz);
        kfree(trips);
-       kfree(tzp);
        kfree(ops);
 }
 
@@ -477,7 +469,7 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
 {
        struct thermal_zone_device *tz;
        struct thermal_trip *trips;
-       struct thermal_zone_params *tzp;
+       struct thermal_zone_params tzp = {};
        struct thermal_zone_device_ops *of_ops;
        struct device_node *np;
        int delay, pdelay;
@@ -509,12 +501,7 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
                goto out_kfree_trips;
        }
 
-       tzp = thermal_of_parameters_init(np);
-       if (IS_ERR(tzp)) {
-               ret = PTR_ERR(tzp);
-               pr_err("Failed to initialize parameter from %pOFn: %d\n", np, ret);
-               goto out_kfree_trips;
-       }
+       thermal_of_parameters_init(np, &tzp);
 
        of_ops->bind = thermal_of_bind;
        of_ops->unbind = thermal_of_unbind;
@@ -522,12 +509,12 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
        mask = GENMASK_ULL((ntrips) - 1, 0);
 
        tz = thermal_zone_device_register_with_trips(np->name, trips, ntrips,
-                                                    mask, data, of_ops, tzp,
+                                                    mask, data, of_ops, &tzp,
                                                     pdelay, delay);
        if (IS_ERR(tz)) {
                ret = PTR_ERR(tz);
                pr_err("Failed to register thermal zone %pOFn: %d\n", np, ret);
-               goto out_kfree_tzp;
+               goto out_kfree_trips;
        }
 
        ret = thermal_zone_device_enable(tz);
@@ -540,8 +527,6 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
 
        return tz;
 
-out_kfree_tzp:
-       kfree(tzp);
 out_kfree_trips:
        kfree(trips);
 out_kfree_of_ops: