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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 37E33C43331 for ; Fri, 3 Apr 2020 01:02:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 145AD20675 for ; Fri, 3 Apr 2020 01:02:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390175AbgDCBCU (ORCPT ); Thu, 2 Apr 2020 21:02:20 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:53778 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731842AbgDCBCU (ORCPT ); Thu, 2 Apr 2020 21:02:20 -0400 Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id E1FB612757492; Thu, 2 Apr 2020 18:02:18 -0700 (PDT) Date: Thu, 02 Apr 2020 18:02:18 -0700 (PDT) Message-Id: <20200402.180218.940555077368617365.davem@davemloft.net> To: leon@kernel.org Cc: kuba@kernel.org, leonro@mellanox.com, arjan@linux.intel.com, xiyou.wangcong@gmail.com, jhs@mojatatu.com, jiri@resnulli.us, netdev@vger.kernel.org, itayav@mellanox.com Subject: Re: [PATCH net] net/sched: Don't print dump stack in event of transmission timeout From: David Miller In-Reply-To: <20200402152336.538433-1-leon@kernel.org> References: <20200402152336.538433-1-leon@kernel.org> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 02 Apr 2020 18:02:19 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Leon Romanovsky Date: Thu, 2 Apr 2020 18:23:36 +0300 > In event of transmission timeout, the drivers are given an opportunity > to recover and continue to work after some in-house cleanups. > > Such event can be caused by HW bugs, wrong congestion configurations > and many more other scenarios. In such case, users are interested to > get a simple "NETDEV WATCHDOG ... " print, which points to the relevant > netdevice in trouble. > > The dump stack printed later was added in the commit b4192bbd85d2 > ("net: Add a WARN_ON_ONCE() to the transmit timeout function") to give > extra information, like list of the modules and which driver is involved. > > While the latter is already printed in "NETDEV WATCHDOG ... ", the list > of modules rarely needed and can be collected later. > > So let's remove the WARN_ONCE() and make dmesg look more user-friendly in > large cluster setups. Software bugs play into these situations and on at least two or three occasions I know that the backtrace hinted at the cause of the bug. I'm not applying this, sorry.