From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] net/sched: reset block pointer in tcf_block_put() Date: Fri, 11 Aug 2017 14:21:00 -0700 (PDT) Message-ID: <20170811.142100.465766359895148878.davem@davemloft.net> References: <20170811203246.GA32076@breakpoint.cc> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: fw@strlen.de, khlebnikov@yandex-team.ru, netdev@vger.kernel.org, jiri@mellanox.com, jhs@mojatatu.com To: xiyou.wangcong@gmail.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:59982 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753256AbdHKVVB (ORCPT ); Fri, 11 Aug 2017 17:21:01 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: From: Cong Wang Date: Fri, 11 Aug 2017 14:06:31 -0700 > On Fri, Aug 11, 2017 at 1:32 PM, Florian Westphal wrote: >> Cong Wang wrote: >>> On Thu, Aug 10, 2017 at 2:31 AM, Konstantin Khlebnikov >>> wrote: >>> > In previous API tcf_destroy_chain() could be called several times and >>> > some schedulers like hfsc and atm use that. In new API tcf_block_put() >>> > frees block but leaves stale pointer, second call will free it once again. >>> >>> Which call path do we call tcf_block_put() for multiple times on >>> the same block? Please be specific, it is not obvious. >> >> you can use tools/testing/selftests/net/rtnetlink.sh to reproduce this >> (kernel panics on delete of root qdisc). > > I am sure this is not how changelog works. We have enough space > in changelog to describe a bug, don't have to leave details in a > following-up email which will almost surely be lost in history. Yeah, the more information in the commit log message the better.