diff --git a/lib/libuutil/uu_avl.c b/lib/libuutil/uu_avl.c
index 040008883a..53def0e073 100644
--- a/lib/libuutil/uu_avl.c
+++ b/lib/libuutil/uu_avl.c
@@ -128,6 +128,7 @@ uu_avl_pool_destroy(uu_avl_pool_t *pp)
 	pp->uap_next->uap_prev = pp->uap_prev;
 	pp->uap_prev->uap_next = pp->uap_next;
 	(void) pthread_mutex_unlock(&uu_apool_list_lock);
+	(void) pthread_mutex_destroy(&pp->uap_lock);
 	pp->uap_prev = NULL;
 	pp->uap_next = NULL;
 	uu_free(pp);