mtd: parsers: ofpart: fix OF node refcount leak in parse_fixed_partitions()

of_get_child_by_name() returns a node pointer with refcount incremented,
which must be released with of_node_put() when done. However, in
parse_fixed_partitions(), when dedicated is true (i.e., a "partitions"
subnode was found), the ofpart_node obtained from of_get_child_by_name()
is never released on any code path.

Add of_node_put(ofpart_node) calls on all exit paths when dedicated is
true to fix the reference count leak.

This bug was detected by our static analysis tool.

Fixes: 562b4e9 ("mtd: parsers: ofpart: fix parsing subpartitions")
Signed-off-by: Weigang He <geoffreyhe2@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

Author: Weigang He

drivers/mtd/parsers/ofpart_core.c

@@ -81,6 +81,7 @@ static int parse_fixed_partitions(struct mtd_info *master,
 	of_id = of_match_node(parse_ofpart_match_table, ofpart_node);
 	if (dedicated && !of_id) {
 		/* The 'partitions' subnode might be used by another parser */
+		of_node_put(ofpart_node);
 		return 0;
 	}
 
@@ -95,12 +96,18 @@ static int parse_fixed_partitions(struct mtd_info *master,
 		nr_parts++;
 	}
 
-	if (nr_parts == 0)
+	if (nr_parts == 0) {
+		if (dedicated)
+			of_node_put(ofpart_node);
 		return 0;
+	}
 
 	parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
-	if (!parts)
+	if (!parts) {
+		if (dedicated)
+			of_node_put(ofpart_node);
 		return -ENOMEM;
+	}
 
 	i = 0;
 	for_each_child_of_node(ofpart_node,  pp) {
@@ -179,6 +186,9 @@ static int parse_fixed_partitions(struct mtd_info *master,
 	if (quirks && quirks->post_parse)
 		quirks->post_parse(master, parts, nr_parts);
 
+	if (dedicated)
+		of_node_put(ofpart_node);
+
 	*pparts = parts;
 	return nr_parts;
 
@@ -187,6 +197,8 @@ static int parse_fixed_partitions(struct mtd_info *master,
 	       master->name, pp, mtd_node);
 	ret = -EINVAL;
 ofpart_none:
+	if (dedicated)
+		of_node_put(ofpart_node);
 	of_node_put(pp);
 	kfree(parts);
 	return ret;