diff --git a/lib/dns/rbt.c b/lib/dns/rbt.c
index ce8e1f3436..34170ce9ab 100644
--- a/lib/dns/rbt.c
+++ b/lib/dns/rbt.c
@@ -2676,6 +2676,7 @@ deletefromlevel(dns_rbtnode_t *item, dns_rbtnode_t **rootp) {
 	 * Fix color violations.
 	 */
 	if (IS_BLACK(item)) {
+		/* cppcheck-suppress nullPointerRedundantCheck symbolName=item */
 		parent = PARENT(item);
 
 		while (child != *rootp && IS_BLACK(child)) {
@@ -2693,6 +2694,7 @@ deletefromlevel(dns_rbtnode_t *item, dns_rbtnode_t **rootp) {
 
 				INSIST(sibling != NULL);
 
+				/* cppcheck-suppress nullPointerRedundantCheck symbolName=sibling */
 				if (IS_BLACK(LEFT(sibling)) &&
 				    IS_BLACK(RIGHT(sibling))) {
 					MAKE_RED(sibling);
@@ -2732,6 +2734,7 @@ deletefromlevel(dns_rbtnode_t *item, dns_rbtnode_t **rootp) {
 
 				INSIST(sibling != NULL);
 
+				/* cppcheck-suppress nullPointerRedundantCheck symbolName=sibling */
 				if (IS_BLACK(LEFT(sibling)) &&
 				    IS_BLACK(RIGHT(sibling))) {
 					MAKE_RED(sibling);
@@ -2863,6 +2866,7 @@ check_properties_helper(dns_rbtnode_t *node) {
 			return (false);
 	}
 
+	/* cppcheck-suppress nullPointerRedundantCheck symbolName=node */
 	if ((DOWN(node) != NULL) && (!IS_ROOT(DOWN(node))))
 		return (false);
 
@@ -2900,12 +2904,15 @@ check_black_distance_helper(dns_rbtnode_t *node, size_t *distance) {
 		return (true);
 	}
 
+	/* cppcheck-suppress nullPointerRedundantCheck symbolName=node */
 	if (!check_black_distance_helper(LEFT(node), &dl))
 		return (false);
 
+	/* cppcheck-suppress nullPointerRedundantCheck symbolName=node */
 	if (!check_black_distance_helper(RIGHT(node), &dr))
 		return (false);
 
+	/* cppcheck-suppress nullPointerRedundantCheck symbolName=node */
 	if (!check_black_distance_helper(DOWN(node), &dd))
 		return (false);