commit 3a2ea636103eaf40404fb82f228605d384c36434

Author: Mark Andrews <marka@isc.org>

Date:   Tue Dec 17 09:08:59 2013 +1100

    3692.   [bug]           Two calls to dns_db_getoriginnode were fatal if there

                            was no data at the node. [RT #35080]

    (cherry picked from commit 161e803a5608956271d8120be37a1b383d14b647)

diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c

index 2dd4aa0..941b77e 100644

--- a/lib/dns/rbtdb.c

+++ b/lib/dns/rbtdb.c

@@ -1638,8 +1638,11 @@ decrement_reference(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,

 	nodelock = &rbtdb->node_locks[bucket];

+#define KEEP_NODE(n, r) \

+	((n)->data != NULL || (n)->down != NULL || (n) == (r)->origin_node)

+

 	/* Handle easy and typical case first. */

-	if (!node->dirty && (node->data != NULL || node->down != NULL)) {

+	if (!node->dirty && KEEP_NODE(node, rbtdb)) {

 		dns_rbtnode_refdecrement(node, &nrefs);

 		INSIST((int)nrefs >= 0);

 		if (nrefs == 0) {

@@ -1708,12 +1711,11 @@ decrement_reference(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node,

 	isc_refcount_decrement(&nodelock->references, &refs);

 	INSIST((int)refs >= 0);

-	/*

-	 * XXXDCL should this only be done for cache zones?

-	 */

-	if (node->data != NULL || node->down != NULL)

+	if (KEEP_NODE(node, rbtdb))

 		goto restore_locks;

+#undef KEEP_NODE

+

 	if (write_locked) {

 		/*

 		 * We can now delete the node.