From: Witold Kręcicki <wpk@isc.org>
Date: Tue, 30 Jun 2020 12:24:12 +0000 (+0200)
Subject: rbtdb: cleanup_dead_nodes should ignore alive nodes on the deadlist
X-Git-Tag: v9.17.3~21^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c8f2d55acf79678801bff0786049451b595563b2;p=thirdparty%2Fbind9.git

rbtdb: cleanup_dead_nodes should ignore alive nodes on the deadlist
---

diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index 87fbdb317b9..c0b34796841 100644
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -1914,15 +1914,16 @@ cleanup_dead_nodes(dns_rbtdb_t *rbtdb, int bucketnum) {
 		ISC_LIST_UNLINK(rbtdb->deadnodes[bucketnum], node, deadlink);
 
 		/*
-		 * Since we're holding a tree write lock, it should be
-		 * impossible for this node to be referenced by others.
-		 *
-		 * decrement_reference may not have tested node->down, as
-		 * the tree_lock was not held, before adding the node to
-		 * deadnodes so we test it here.
+		 * We might have reactivated this node without a tree write
+		 * lock, so we couldn't remove this node from deadnodes then
+		 * and we have to do it now.
 		 */
-		INSIST(isc_refcount_current(&node->references) == 0 &&
-		       node->data == NULL);
+		if (isc_refcount_current(&node->references) != 0 ||
+		    node->data != NULL) {
+			node = ISC_LIST_HEAD(rbtdb->deadnodes[bucketnum]);
+			count--;
+			continue;
+		}
 
 		if (is_leaf(node) && rbtdb->task != NULL) {
 			send_to_prune_tree(rbtdb, node, isc_rwlocktype_write);