diff --git a/base/data-struct/radix-tree-adaptive.c b/base/data-struct/radix-tree-adaptive.c
index cbe8302c3..f5a8606d3 100644
--- a/base/data-struct/radix-tree-adaptive.c
+++ b/base/data-struct/radix-tree-adaptive.c
@@ -564,6 +564,8 @@ static void _degrade_to_n4(struct node16 *n16, struct value *result)
 {
         struct node4 *n4 = zalloc(sizeof(*n4));
 
+	assert(n4 != NULL);
+
         n4->nr_entries = n16->nr_entries;
         memcpy(n4->keys, n16->keys, n16->nr_entries * sizeof(*n4->keys));
         memcpy(n4->values, n16->values, n16->nr_entries * sizeof(*n4->values));
@@ -578,6 +580,8 @@ static void _degrade_to_n16(struct node48 *n48, struct value *result)
 	unsigned i, count = 0;
         struct node16 *n16 = zalloc(sizeof(*n16));
 
+	assert(n16 != NULL);
+
         n16->nr_entries = n48->nr_entries;
         for (i = 0; i < 256; i++) {
 	        if (n48->keys[i] < 48) {
@@ -598,6 +602,8 @@ static void _degrade_to_n48(struct node256 *n256, struct value *result)
         unsigned i, count = 0;
         struct node48 *n48 = zalloc(sizeof(*n48));
 
+	assert(n48 != NULL);
+
         n48->nr_entries = n256->nr_entries;
         for (i = 0; i < 256; i++) {
 		if (n256->values[i].type == UNSET)