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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 AE55EC43331 for ; Fri, 3 Apr 2020 04:36:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C7F2208E4 for ; Fri, 3 Apr 2020 04:36:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585888577; bh=byoj0iOToaAWYh4X7UpbWQ4AlmV82wfYO9qZNoc0RYE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=lJwBv4ice/kgjwQhVYBriR1vBnXNhSGLnDvXUU50lGBwmV9VwR++4hBYxyFngmdHy OOPis8Q+ZDtWw4VFsqCiQd8Z3G2PiJyORSSWrzqooFqW3BesrJ/iPLn1faZDRAZtZq rXJExFQCPBZUpoFNLARGDPs/NmQFDgbv/qt/C9uw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731967AbgDCEgQ (ORCPT ); Fri, 3 Apr 2020 00:36:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:41198 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725851AbgDCEgQ (ORCPT ); Fri, 3 Apr 2020 00:36:16 -0400 Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C5BAE2063A; Fri, 3 Apr 2020 04:36:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585888575; bh=byoj0iOToaAWYh4X7UpbWQ4AlmV82wfYO9qZNoc0RYE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=apdFQpotFUkLFwF5qUsjNWvcUM/JdCXWUdeUfs0qUNTeqGJOCzBVYk8bMzeeS76RZ jXxwZsd7nJvM0d3ah+89gw/8ezXbzYkTzrZgqyMD4iif+QMLrUAFaFcZ25kqxCinJJ Ew1RAWdzZzqOq16dw1U5FcdgBiwgvLKUfEd4hoog= Date: Fri, 3 Apr 2020 07:36:11 +0300 From: Leon Romanovsky To: Cong Wang Cc: David Miller , Jakub Kicinski , Arjan van de Ven , Jamal Hadi Salim , Jiri Pirko , Linux Kernel Network Developers , itayav@mellanox.com Subject: Re: [PATCH net] net/sched: Don't print dump stack in event of transmission timeout Message-ID: <20200403043611.GC80989@unreal> References: <20200402152336.538433-1-leon@kernel.org> <20200402.180218.940555077368617365.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Apr 02, 2020 at 09:30:15PM -0700, Cong Wang wrote: > On Thu, Apr 2, 2020 at 6:02 PM David Miller wrote: > > > > 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 don't see how a timer stack trace could help to debug this issue > in any scenario, the messages out of this stack trace are indeed > helpful. > > On the other hand, a stack trace does help to get some attention > via ABRT, but at least for us we now use rasdaemon to capture > this, so I am 100% fine to remove this stack trace. Thanks > > Thanks.