[PATCH v3] pinctrl: generic: free maps on pinctrl_generic_to_map() failure

[kr494167@gmail.com]

From: Surendra Singh Chouhan <kr494167@gmail.com>

pinctrl_generic_to_map() parses DT configuration and allocates pinctrl
maps via pinctrl_utils_reserve_map().

If subsequent steps (such as pinctrl_utils_add_map_mux(),
pinctrl_generic_add_group(), pinconf_generic_parse_dt_config(), or
pinctrl_utils_add_map_configs()) return an error, *maps may contain
partially allocated map entries. Returning the error directly without
freeing *maps leaks the allocated mapping memory across all drivers
that rely on pinctrl_generic_to_map().

Fix this by calling pinctrl_utils_free_map() and resetting *maps,
*num_maps, and *num_reserved_maps in the error path of
pinctrl_generic_to_map().

Fixes: aaaf31be0426 ("pinctrl: extract pinctrl_generic_to_map() from pinctrl_generic_pins_function_dt_node_to_map()")
Signed-off-by: Surendra Singh Chouhan <kr494167@gmail.com>
---
v3:
 - Clean up pinctrl-generic.c changes cleanly to apply cleanly on linusw/pinctrl.git devel branch.
v2:
 - Move map cleanup inside pinctrl_generic_to_map() helper in pinctrl-generic.c
   so all callers are protected from memory leaks, as suggested by Frank Li.

 drivers/pinctrl/pinctrl-generic.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-generic.c b/drivers/pinctrl/pinctrl-generic.c
index 9759b0186bcc..fd6bdb74028a 100644
--- a/drivers/pinctrl/pinctrl-generic.c
+++ b/drivers/pinctrl/pinctrl-generic.c
@@ -42,33 +42,44 @@ int pinctrl_generic_to_map(struct pinctrl_dev *pctldev, struct device_node *pare
 	ret = pinctrl_utils_add_map_mux(pctldev, maps, num_reserved_maps, num_maps, group_name,
 					parent->name);
 	if (ret < 0)
-		return ret;
+		goto err_free_map;
 
 	ret = pinctrl_generic_add_group(pctldev, group_name, pins, npins, data);
-	if (ret < 0)
-		return dev_err_probe(dev, ret, "failed to add group %s: %d\n",
+	if (ret < 0) {
+		dev_err_probe(dev, ret, "failed to add group %s: %d\n",
 				     group_name, ret);
+		goto err_free_map;
+	}
 
 	ret = pinconf_generic_parse_dt_config(np, pctldev, &configs, &num_configs);
-	if (ret)
-		return dev_err_probe(dev, ret, "failed to parse pin config of group %s\n",
+	if (ret) {
+		dev_err_probe(dev, ret, "failed to parse pin config of group %s\n",
 			group_name);
+		goto err_free_map;
+	}
 
 	if (num_configs == 0)
 		return 0;
 
 	ret = pinctrl_utils_reserve_map(pctldev, maps, num_reserved_maps, num_maps, reserve);
 	if (ret)
-		return ret;
+		goto err_free_map;
 
 	ret = pinctrl_utils_add_map_configs(pctldev, maps, num_reserved_maps, num_maps, group_name,
 					    configs,
 			num_configs, PIN_MAP_TYPE_CONFIGS_GROUP);
 	kfree(configs);
 	if (ret)
-		return ret;
+		goto err_free_map;
 
 	return 0;
+
+err_free_map:
+	pinctrl_utils_free_map(pctldev, *maps, *num_maps);
+	*maps = NULL;
+	*num_maps = 0;
+	*num_reserved_maps = 0;
+	return ret;
 };
 EXPORT_SYMBOL_GPL(pinctrl_generic_to_map);
 
-- 
2.55.0