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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 D60F0C43603 for ; Thu, 19 Dec 2019 02:40:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DDF7227BF for ; Thu, 19 Dec 2019 02:40:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KwMQp5jY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726874AbfLSCkk (ORCPT ); Wed, 18 Dec 2019 21:40:40 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:34006 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbfLSCkk (ORCPT ); Wed, 18 Dec 2019 21:40:40 -0500 Received: by mail-pj1-f66.google.com with SMTP id s94so1961194pjc.1; Wed, 18 Dec 2019 18:40:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding:content-language; bh=0RBVyIP0Ujh+br/1IluUkRXVcIUAcx75iz4VOyZAsEM=; b=KwMQp5jYrub3Gax4KKL+SGhnfNHi2oLQhwCHetSJud5dK4mBgnW1PqRgZkCWmpkFSJ 6gNmVp69VlJatXBvlFUGKlTBB/qRfjIQb7nZS/GiN73f5crkOI4J43oAc76n7qsMAP4Q UF2wzSUECYKOHRPzV0uRMRtDXFGjTXuOaeTTTXCGwv0+nAuT9cRYexHPhDzLC/rOzKVQ R9xG3yUS/9gLRVdWICBjdbwIoODiPWZnJ6HjggRCa6dzrkyExth/LO9FWBin8yfdKKPy YDuwoXeZQfnylEEz22ECPYVp7KyKdycGX2EF62IApfpIGaWlZqpQaGIxhOHAAe/b4l7J WTcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=0RBVyIP0Ujh+br/1IluUkRXVcIUAcx75iz4VOyZAsEM=; b=UkvtdWRckLeWtpwN9jnLQhhRfo5J8JPlCt+AIo0xGMFsPf5e4pNxf34/92wl8aBLB4 vZFQqy074HcPMcpEAYYntEeY5YFHAnJdpev0IBwYJRo0MNiVQcNSVxmgwf+04XGYKCJD +0rGwIeRilxugepvfLXnIylrBC0lE0TQn7u6OL6Elhw/Y8D3xh1+dghMsAikpmUrEtcy 0OfSMIcXuWbR8JgnK0n+f7ICMnsmmVjAw/FAaRIeJmdgwXqOe/Q8x6ydG4kJUoPrylxX jym5zBm1o0Fayj+D1SRhhPc+TTNkd+vaq94kU8mgnZCnTPgNtbvbiqtCbIuxDBraUqnc N2hg== X-Gm-Message-State: APjAAAUJcLN8oABnVl07/39qfG/GZYMGj9V4ZUdsRPx494rFrRPQ3yvv yF2RdF4B2pCVrGSLSonr/yhxeeWEO+c4Vw== X-Google-Smtp-Source: APXvYqz/Cd0MXX935OoQP3cfj8uUp1E1rKNWnT/21KyaATPnsDVpivZCkyWMLxo2BYUXfQbpmjk5wQ== X-Received: by 2002:a17:90a:20c4:: with SMTP id f62mr6940929pjg.70.1576723239163; Wed, 18 Dec 2019 18:40:39 -0800 (PST) Received: from ?IPv6:2402:f000:1:1501:200:5efe:166.111.139.116? ([2402:f000:1:1501:200:5efe:a66f:8b74]) by smtp.gmail.com with ESMTPSA id d13sm4321448pjx.21.2019.12.18.18.40.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Dec 2019 18:40:38 -0800 (PST) Subject: Re: [PATCH] net: amd: xgbe: fix possible sleep-in-atomic-context bugs in xgbe_powerdown() To: David Miller Cc: thomas.lendacky@amd.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20191218140102.11579-1-baijiaju1990@gmail.com> <20191218.132601.160360469201947283.davem@davemloft.net> From: Jia-Ju Bai Message-ID: <62131c40-e69b-0664-2b2a-177a031a6f1f@gmail.com> Date: Thu, 19 Dec 2019 10:40:39 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 In-Reply-To: <20191218.132601.160360469201947283.davem@davemloft.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/12/19 5:26, David Miller wrote: > 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. Looking at the code, only xgbe_powerup() and xgbe_powerdown() use the spinlock "pdata->lock". How about change the spinlock to a mutex? Best wishes, Jia-Ju Bai