diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index a81a45700cc..fd7a9c14ba7 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -1863,13 +1863,24 @@ PortalLockCachedPlan(Portal portal, bool do_prep,
 	else if (AcquireExecutorLocks(portal->cplan))
 		return false;
 
-	/* Replan.  Locks will be taken freshly. */
-	ReleaseCachedPlan(portal->cplan, portal->resowner);
+	/*
+	 * Replan.  Locks will be taken freshly.
+	 *
+	 * The portal's reference to its cached plan is acquired with a NULL
+	 * owner, both by ExecuteQuery() and by exec_bind_message(), and
+	 * PortalReleaseCachedPlan() releases it the same way.  Keep the
+	 * replacement reference on that same footing: handing portal->resowner
+	 * here would release a reference that resource owner never owned, and
+	 * register the new one where nothing will release it.  The locks taken
+	 * below do belong to portal->resowner, which is why ExecutorPrepAndLock()
+	 * above still gets it.
+	 */
+	ReleaseCachedPlan(portal->cplan, NULL);
 	portal->cplan = NULL;
 	portal->stmts = NIL;
 	portal->cplan = GetCachedPlan(portal->plansource,
 								  portal->portalParams,
-								  portal->resowner,
+								  NULL,
 								  portal->queryEnv);
 	portal->stmts = portal->cplan->stmt_list;
 	portal->strategy = ChoosePortalStrategy(portal->stmts);