From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6CB71C6778A for ; Sun, 22 Jul 2018 09:02:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 215C52086A for ; Sun, 22 Jul 2018 09:02:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 215C52086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728332AbeGVJ6r (ORCPT ); Sun, 22 Jul 2018 05:58:47 -0400 Received: from Chamillionaire.breakpoint.cc ([146.0.238.67]:32826 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727990AbeGVJ6q (ORCPT ); Sun, 22 Jul 2018 05:58:46 -0400 Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.89) (envelope-from ) id 1fhAGA-0000tu-6X; Sun, 22 Jul 2018 11:02:34 +0200 Date: Sun, 22 Jul 2018 11:02:34 +0200 From: Florian Westphal To: Shaochun Chen Cc: pablo@netfilter.org, kadlec@blackhole.kfki.hu, fw@strlen.de, davem@davemloft.net, johannes.berg@intel.com, pombredanne@nexb.com, kstewart@linuxfoundation.org, gregkh@linuxfoundation.org, Jason@zx2c4.com, dsahern@gmail.com, lucien.xin@gmail.com, ktkhai@virtuozzo.com, xiyou.wangcong@gmail.com, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, tom@quantonium.net Subject: Re: [PATCH] netlink: fix memory leak Message-ID: <20180722090234.bttpk2xmwf4d7hfo@breakpoint.cc> References: <20180722024925.3176-1-cscnull@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180722024925.3176-1-cscnull@gmail.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Shaochun Chen wrote: [ CC Tom Herbert ] > and the memory which pointed by control->data will leak. so if netlink_dump > start fail, call control->done to free the memory. Tom, I was about to suggest moving extra allocations for dumps into a ->start() callback whereever possible. However, it looks like ->done() is not guaranteed to be called even if ->start() was invoked, but it seems at least ila assumes ->done always cleans up after ->start. I am looking at netlink_dump(); it calls ->done() only after the dump callback was invoked. In nf_tables_api.c case it might be possible to defer allocations until ->dump() is called for first time via cb_args but I don't think its going to be any better than cleaning up manually after netlink_dump_start() returned an error. Any better ideas or advice on how to procceed? Thanks!