From fb1c018eccd390595fc2806580064a2db70fc99f Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Mon, 22 Jun 2009 03:53:05 +0000
Subject: [PATCH] 2589.   [bug]           dns_db_unregister() failed to clear
 '*dbimp'.                         [RT #19626]

---
 CHANGES      | 3 +++
 lib/dns/db.c | 4 +++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index df04821979..8628dbc1db 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,9 @@
 2613.	[bug]		Option argument validation was missing for
 			dnssec-dsfromkey. [RT #19828]
 
+2589.	[bug]		dns_db_unregister() failed to clear '*dbimp'.
+		        [RT #19626]
+
 2581.	[contrib]	dlz/mysql set MYSQL_OPT_RECONNECT option on connection.
 			Requires MySQL 5.0.19 or later. [RT #19084]
 
diff --git a/lib/dns/db.c b/lib/dns/db.c
index a4c2864170..d58d74bcd8 100644
--- a/lib/dns/db.c
+++ b/lib/dns/db.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: db.c,v 1.88 2008/09/24 02:46:22 marka Exp $ */
+/* $Id: db.c,v 1.88.50.1 2009/06/22 03:53:05 marka Exp $ */
 
 /*! \file */
 
@@ -854,12 +854,14 @@ dns_db_unregister(dns_dbimplementation_t **dbimp) {
 	RUNTIME_CHECK(isc_once_do(&once, initialize) == ISC_R_SUCCESS);
 
 	imp = *dbimp;
+	*dbimp = NULL;
 	RWLOCK(&implock, isc_rwlocktype_write);
 	ISC_LIST_UNLINK(implementations, imp, link);
 	mctx = imp->mctx;
 	isc_mem_put(mctx, imp, sizeof(dns_dbimplementation_t));
 	isc_mem_detach(&mctx);
 	RWUNLOCK(&implock, isc_rwlocktype_write);
+	ENSURE(*dbimp == NULL);
 }
 
 isc_result_t