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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 677EAC76186 for ; Wed, 17 Jul 2019 08:23:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 469CE20818 for ; Wed, 17 Jul 2019 08:23:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728016AbfGQIX5 (ORCPT ); Wed, 17 Jul 2019 04:23:57 -0400 Received: from mx2.suse.de ([195.135.220.15]:57702 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725912AbfGQIX5 (ORCPT ); Wed, 17 Jul 2019 04:23:57 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E2C3CAEA4; Wed, 17 Jul 2019 08:23:55 +0000 (UTC) Date: Wed, 17 Jul 2019 17:23:40 +0900 From: Benjamin Poirier To: Firo Yang Cc: David Miller , Ajit Khaparde , Sathya Perla , Somnath Kotur , Sriharsha Basavapatna , Saeed Mahameed , "netdev@vger.kernel.org" Subject: Re: [PATCH net] be2net: Signal that the device cannot transmit during reconfiguration Message-ID: <20190717082340.GA6015@f1> References: <20190716081655.7676-1-bpoirier@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2019/07/17 13:23, Firo Yang wrote: > I think there is a problem if dev_watchdog() is triggered before netif_carrier_off(). dev_watchdog() might call ->ndo_tx_timeout(), i.e. be_tx_timeout(), if txq timeout happens. Thus be_tx_timeout() could still be able to access the memory which is being freed by be_update_queues(). Good point. That's a separate problem which would occur in case of real tx timeout. How about this followup change: --- a/drivers/net/ethernet/emulex/benet/be_main.c +++ b/drivers/net/ethernet/emulex/benet/be_main.c @@ -4698,8 +4698,13 @@ int be_update_queues(struct be_adapter *adapter) int status; if (netif_running(netdev)) { + /* be_tx_timeout() must not run concurrently with this + * function, synchronize with an already-running dev_watchdog + */ + netif_tx_lock_bh(netdev); /* device cannot transmit now, avoid dev_watchdog timeouts */ netif_carrier_off(netdev); + netif_tx_unlock_bh(netdev); be_close(netdev); }