diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index dcc1dd96911a..adb26aff481d 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -205,7 +205,7 @@ static void populate_properties(const void *blob,
 		*pprev = NULL;
 }
 
-static bool populate_node(const void *blob,
+static int populate_node(const void *blob,
 			  int offset,
 			  void **mem,
 			  struct device_node *dad,
@@ -214,24 +214,24 @@ static bool populate_node(const void *blob,
 {
 	struct device_node *np;
 	const char *pathp;
-	unsigned int l, allocl;
+	int len;
 
-	pathp = fdt_get_name(blob, offset, &l);
+	pathp = fdt_get_name(blob, offset, &len);
 	if (!pathp) {
 		*pnp = NULL;
-		return false;
+		return len;
 	}
 
-	allocl = ++l;
+	len++;
 
-	np = unflatten_dt_alloc(mem, sizeof(struct device_node) + allocl,
+	np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len,
 				__alignof__(struct device_node));
 	if (!dryrun) {
 		char *fn;
 		of_node_init(np);
 		np->full_name = fn = ((char *)np) + sizeof(*np);
 
-		memcpy(fn, pathp, l);
+		memcpy(fn, pathp, len);
 
 		if (dad != NULL) {
 			np->parent = dad;
@@ -295,6 +295,7 @@ static int unflatten_dt_nodes(const void *blob,
 	struct device_node *nps[FDT_MAX_DEPTH];
 	void *base = mem;
 	bool dryrun = !base;
+	int ret;
 
 	if (nodepp)
 		*nodepp = NULL;
@@ -322,9 +323,10 @@ static int unflatten_dt_nodes(const void *blob,
 		    !of_fdt_device_is_available(blob, offset))
 			continue;
 
-		if (!populate_node(blob, offset, &mem, nps[depth],
-				   &nps[depth+1], dryrun))
-			return mem - base;
+		ret = populate_node(blob, offset, &mem, nps[depth],
+				   &nps[depth+1], dryrun);
+		if (ret < 0)
+			return ret;
 
 		if (!dryrun && nodepp && !*nodepp)
 			*nodepp = nps[depth+1];
@@ -372,6 +374,10 @@ void *__unflatten_device_tree(const void *blob,
 {
 	int size;
 	void *mem;
+	int ret;
+
+	if (mynodes)
+		*mynodes = NULL;
 
 	pr_debug(" -> unflatten_device_tree()\n");
 
@@ -392,7 +398,7 @@ void *__unflatten_device_tree(const void *blob,
 
 	/* First pass, scan for size */
 	size = unflatten_dt_nodes(blob, NULL, dad, NULL);
-	if (size < 0)
+	if (size <= 0)
 		return NULL;
 
 	size = ALIGN(size, 4);
@@ -410,12 +416,16 @@ void *__unflatten_device_tree(const void *blob,
 	pr_debug("  unflattening %p...\n", mem);
 
 	/* Second pass, do actual unflattening */
-	unflatten_dt_nodes(blob, mem, dad, mynodes);
+	ret = unflatten_dt_nodes(blob, mem, dad, mynodes);
+
 	if (be32_to_cpup(mem + size) != 0xdeadbeef)
 		pr_warn("End of tree marker overwritten: %08x\n",
 			be32_to_cpup(mem + size));
 
-	if (detached && mynodes) {
+	if (ret <= 0)
+		return NULL;
+
+	if (detached && mynodes && *mynodes) {
 		of_node_set_flag(*mynodes, OF_DETACHED);
 		pr_debug("unflattened tree is detached\n");
 	}
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 50bbe0edf538..e12c643b6ba8 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -1017,7 +1017,7 @@ int of_overlay_fdt_apply(const void *overlay_fdt, u32 overlay_fdt_size,
 	const void *new_fdt;
 	int ret;
 	u32 size;
-	struct device_node *overlay_root;
+	struct device_node *overlay_root = NULL;
 
 	*ovcs_id = 0;
 	ret = 0;
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index eb100627c186..f9b5b698249f 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -1408,7 +1408,7 @@ static void attach_node_and_children(struct device_node *np)
 static int __init unittest_data_add(void)
 {
 	void *unittest_data;
-	struct device_node *unittest_data_node, *np;
+	struct device_node *unittest_data_node = NULL, *np;
 	/*
 	 * __dtb_testcases_begin[] and __dtb_testcases_end[] are magically
 	 * created by cmd_dt_S_dtb in scripts/Makefile.lib
@@ -1417,10 +1417,10 @@ static int __init unittest_data_add(void)
 	extern uint8_t __dtb_testcases_end[];
 	const int size = __dtb_testcases_end - __dtb_testcases_begin;
 	int rc;
+	void *ret;
 
 	if (!size) {
-		pr_warn("%s: No testcase data to attach; not running tests\n",
-			__func__);
+		pr_warn("%s: testcases is empty\n", __func__);
 		return -ENODATA;
 	}
 
@@ -1429,9 +1429,14 @@ static int __init unittest_data_add(void)
 	if (!unittest_data)
 		return -ENOMEM;
 
-	of_fdt_unflatten_tree(unittest_data, NULL, &unittest_data_node);
+	ret = of_fdt_unflatten_tree(unittest_data, NULL, &unittest_data_node);
+	if (!ret) {
+		pr_warn("%s: unflatten testcases tree failed\n", __func__);
+		kfree(unittest_data);
+		return -ENODATA;
+	}
 	if (!unittest_data_node) {
-		pr_warn("%s: No tree to attach; not running tests\n", __func__);
+		pr_warn("%s: testcases tree is empty\n", __func__);
 		kfree(unittest_data);
 		return -ENODATA;
 	}