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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 EB83EC5DF62 for ; Wed, 6 Nov 2019 08:17:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD75A2178F for ; Wed, 6 Nov 2019 08:17:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573028278; bh=sLUI4kmQl3FANkvcg5y8DlLtS05Kk9CCcDds+WfPefU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=kSKhIbxFqOEt6EDH9DB0kwj6hApAzHYEMgp7zh/zg1iN7gDw5F7qThRowFOK7LUfw G1Bx7OjBfIarqclh+4c4GFYoxOlHuEWUFdNExL34LdV+NAVrPxaNmxX9ZJ1c2XCe+a mEk127RGMsDZjdBdnRYXYObmZ/vu8wZOmxekctSM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730112AbfKFIR6 (ORCPT ); Wed, 6 Nov 2019 03:17:58 -0500 Received: from inca-roads.misterjones.org ([213.251.177.50]:46918 "EHLO inca-roads.misterjones.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729881AbfKFIR5 (ORCPT ); Wed, 6 Nov 2019 03:17:57 -0500 Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why) by cheepnis.misterjones.org with esmtpsa (TLSv1.2:AES256-GCM-SHA384:256) (Exim 4.80) (envelope-from ) id 1iSGVn-0005sT-OM; Wed, 06 Nov 2019 09:17:55 +0100 Date: Wed, 6 Nov 2019 08:17:48 +0000 From: Marc Zyngier To: Salil Mehta Cc: "netdev@vger.kernel.org" , "lipeng (Y)" , "Zhuangyuzeng (Yisen)" , "David S . Miller" Subject: Re: [PATCH] net: hns: Ensure that interface teardown cannot race with TX interrupt Message-ID: <20191106081748.0e21554c@why> In-Reply-To: References: <20191104195604.17109-1-maz@kernel.org> Organization: Approximate X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: salil.mehta@huawei.com, netdev@vger.kernel.org, lipeng321@huawei.com, yisen.zhuang@huawei.com, davem@davemloft.net X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on cheepnis.misterjones.org); SAEximRunCond expanded to false Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, 5 Nov 2019 18:41:11 +0000 Salil Mehta wrote: Hi Salil, > Hi Marc, > I tested with the patch on D05 with the lockdep enabled kernel with below options > and I could not reproduce the deadlock. I do not argue the issue being mentioned > as this looks to be a clear bug which should hit while TX data-path is running > and we try to disable the interface. Lockdep screaming at you doesn't mean the deadly scenario happens in practice, and I've never seen the machine hanging in these conditions. But I've also never tried to trigger it in anger. > Could you please help me know the exact set of steps you used to get into this > problem. Also, are you able to re-create it easily/frequently? I just need to issue "reboot" (which calls "ip link ... down") for this to trigger. Here's a full splat[1], as well as my full config[2]. It is 100% repeatable. > # Kernel Config options: > CONFIG_LOCKDEP_SUPPORT=y > CONFIG_LOCKDEP=y You'll need at least CONFIG_PROVE_LOCKING=y CONFIG_NET_POLL_CONTROLLER=y in order to hit it. Thanks, M. [1] https://paste.debian.net/1114451/ [2] https://paste.debian.net/1114472/ -- Jazz is not dead. It just smells funny...