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 AFDC9C43603 for ; Wed, 18 Dec 2019 21:26:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CEB7218AC for ; Wed, 18 Dec 2019 21:26:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726670AbfLRV0G (ORCPT ); Wed, 18 Dec 2019 16:26:06 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:56644 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725991AbfLRV0F (ORCPT ); Wed, 18 Dec 2019 16:26:05 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:1c3::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 D3114153DBDAA; Wed, 18 Dec 2019 13:26:03 -0800 (PST) Date: Wed, 18 Dec 2019 13:26:01 -0800 (PST) Message-Id: <20191218.132601.160360469201947283.davem@davemloft.net> To: baijiaju1990@gmail.com Cc: thomas.lendacky@amd.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: amd: xgbe: fix possible sleep-in-atomic-context bugs in xgbe_powerdown() From: David Miller In-Reply-To: <20191218140102.11579-1-baijiaju1990@gmail.com> References: <20191218140102.11579-1-baijiaju1990@gmail.com> 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]); Wed, 18 Dec 2019 13:26:04 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jia-Ju Bai Date: Wed, 18 Dec 2019 22:01:02 +0800 > @@ -1257,17 +1257,18 @@ int xgbe_powerdown(struct net_device *netdev, unsigned int caller) > netif_tx_stop_all_queues(netdev); > > xgbe_stop_timers(pdata); > - flush_workqueue(pdata->dev_workqueue); > > hw_if->powerdown_tx(pdata); > hw_if->powerdown_rx(pdata); > > - xgbe_napi_disable(pdata, 0); > - > pdata->power_down = 1; > > spin_unlock_irqrestore(&pdata->lock, flags); > > + flush_workqueue(pdata->dev_workqueue); > + > + xgbe_napi_disable(pdata, 0); > + Nope, this doesn't work at all. You can't leave NAPI enabled, and thus packet processing, after the TX and RX units of the chip have been powered down.