[PATCH] of: overlay: add_changeset_property() memory leak

[frowand.list@gmail.com]

From: Frank Rowand <frank.rowand@sony.com>

No changeset entries are created for #address-cells and #size-cells
properties, but the duplicated properties are never freed.  This
results in a memory leak which is detected by kmemleak:

 unreferenced object 0x85887180 (size 64):
   backtrace:
     kmem_cache_alloc_trace+0x1fb/0x1fc
     __of_prop_dup+0x25/0x7c
     add_changeset_property+0x17f/0x370
     build_changeset_next_level+0x29/0x20c
     of_overlay_fdt_apply+0x32b/0x6b4
     ...

Fixes: 6f75118800acf77f8 ("of: overlay: validate overlay properties #address-cells and #size-cells")
Reported-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Frank Rowand <frank.rowand@sony.com>
---
 drivers/of/overlay.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index c423e94baf0f..9617b7df7c4d 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -305,7 +305,6 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
 {
 	struct property *new_prop = NULL, *prop;
 	int ret = 0;
-	bool check_for_non_overlay_node = false;
 
 	if (target->in_livetree)
 		if (!of_prop_cmp(overlay_prop->name, "name") ||
@@ -318,6 +317,25 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
 	else
 		prop = NULL;
 
+	if (prop) {
+		if (!of_prop_cmp(prop->name, "#address-cells")) {
+			if (!of_prop_val_eq(prop, overlay_prop)) {
+				pr_err("ERROR: changing value of #address-cells is not allowed in %pOF\n",
+				       target->np);
+				ret = -EINVAL;
+			}
+			return ret;
+
+		} else if (!of_prop_cmp(prop->name, "#size-cells")) {
+			if (!of_prop_val_eq(prop, overlay_prop)) {
+				pr_err("ERROR: changing value of #size-cells is not allowed in %pOF\n",
+				       target->np);
+				ret = -EINVAL;
+			}
+			return ret;
+		}
+	}
+
 	if (is_symbols_prop) {
 		if (prop)
 			return -EINVAL;
@@ -330,33 +348,18 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
 		return -ENOMEM;
 
 	if (!prop) {
-		check_for_non_overlay_node = true;
 		if (!target->in_livetree) {
 			new_prop->next = target->np->deadprops;
 			target->np->deadprops = new_prop;
 		}
 		ret = of_changeset_add_property(&ovcs->cset, target->np,
 						new_prop);
-	} else if (!of_prop_cmp(prop->name, "#address-cells")) {
-		if (!of_prop_val_eq(prop, new_prop)) {
-			pr_err("ERROR: changing value of #address-cells is not allowed in %pOF\n",
-			       target->np);
-			ret = -EINVAL;
-		}
-	} else if (!of_prop_cmp(prop->name, "#size-cells")) {
-		if (!of_prop_val_eq(prop, new_prop)) {
-			pr_err("ERROR: changing value of #size-cells is not allowed in %pOF\n",
-			       target->np);
-			ret = -EINVAL;
-		}
 	} else {
-		check_for_non_overlay_node = true;
 		ret = of_changeset_update_property(&ovcs->cset, target->np,
 						   new_prop);
 	}
 
-	if (check_for_non_overlay_node &&
-	    !of_node_check_flag(target->np, OF_OVERLAY))
+	if (!of_node_check_flag(target->np, OF_OVERLAY))
 		pr_err("WARNING: memory leak will occur if overlay removed, property: %pOF/%s\n",
 		       target->np, new_prop->name);
 
-- 
Frank Rowand <frank.rowand@sony.com>