daemon: fixed race condition when canceling one event multiple times

daemon/bindings.c

@@ -495,7 +495,9 @@ static void event_callback(uv_timer_t *timer)
 	int ret = execute_callback(L, 1);
 	/* Free callback if not recurrent or an error */
 	if (ret != 0 || uv_timer_get_repeat(timer) == 0) {
-		uv_close((uv_handle_t *)timer, (uv_close_cb) event_free);
+		if (!uv_is_closing((uv_handle_t *)timer)) {
+			uv_close((uv_handle_t *)timer, (uv_close_cb) event_free);
+		}
 	}
 }
 
@@ -572,7 +574,9 @@ static int event_cancel(lua_State *L)
 	/* Close the timer */
 	lua_rawgeti(L, -1, 2);
 	uv_handle_t *timer = lua_touserdata(L, -1);
-	uv_close(timer, (uv_close_cb) event_free);
+	if (!uv_is_closing(timer)) {
+		uv_close(timer, (uv_close_cb) event_free);
+	}
 	lua_pushboolean(L, true);
 	return 1;
 }

daemon/lua/trust_anchors.lua

@@ -89,7 +89,6 @@ end
 
 -- Plan refresh event and re-schedule itself based on the result of the callback
 local function refresh_plan(trust_anchors, timeout, refresh_cb)
-	if trust_anchors.refresh_ev ~= nil then event.cancel(trust_anchors.refresh_ev) end
 	trust_anchors.refresh_ev = event.after(timeout, function (ev)
 		resolve('.', kres.type.DNSKEY, kres.class.IN, kres.query.NO_CACHE,
 		function (pkt)
@@ -198,6 +197,7 @@ local trust_anchors = {
 		if is_unmanaged then trust_anchors.file_current = nil end
 		trust_anchors.keyset = {}
 		if trust_anchors.update(new_keys, true) then
+			if trust_anchors.refresh_ev ~= nil then event.cancel(trust_anchors.refresh_ev) end
 			refresh_plan(trust_anchors, sec, active_refresh)
 		end
 	end,