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=-1.0 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 686FAC433E0 for ; Wed, 24 Jun 2020 03:23:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36E4920767 for ; Wed, 24 Jun 2020 03:23:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388638AbgFXDX1 (ORCPT ); Tue, 23 Jun 2020 23:23:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32796 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387985AbgFXDX0 (ORCPT ); Tue, 23 Jun 2020 23:23:26 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C44BC061573; Tue, 23 Jun 2020 20:23:26 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::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 5033A1298361E; Tue, 23 Jun 2020 20:23:25 -0700 (PDT) Date: Tue, 23 Jun 2020 20:23:24 -0700 (PDT) Message-Id: <20200623.202324.442008830004872069.davem@davemloft.net> To: likaige@loongson.cn Cc: benve@cisco.com, _govind@gmx.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, lixuefeng@loongson.cn, yangtiezhu@loongson.cn Subject: Re: [PATCH RESEND] net/cisco: Fix a sleep-in-atomic-context bug in enic_init_affinity_hint() From: David Miller In-Reply-To: <7533075e-0e8e-2fde-c8fa-72e2ea222176@loongson.cn> References: <20200623.143311.995885759487352025.davem@davemloft.net> <20200623.152626.2206118203643133195.davem@davemloft.net> <7533075e-0e8e-2fde-c8fa-72e2ea222176@loongson.cn> X-Mailer: Mew version 6.8 on Emacs 26.3 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]); Tue, 23 Jun 2020 20:23:25 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kaige Li Date: Wed, 24 Jun 2020 09:56:47 +0800 > > On 06/24/2020 06:26 AM, David Miller wrote: >> From: David Miller >> Date: Tue, 23 Jun 2020 14:33:11 -0700 (PDT) >> >>> Calling a NIC driver open function from a context holding a spinlock >>> is very much the real problem, so many operations have to sleep and >>> in face that ->ndo_open() method is defined as being allowed to sleep >>> and that's why the core networking never invokes it with spinlocks >> ^^^^ >> >> I mean "without" of course. :-) >> >>> held. > > Did you mean that open function should be out of spinlock? If so, I > will > send V2 patch. Yes, but only if that is safe. You have to analyze the locking done by this driver and fix it properly. I anticipate it is not just a matter of changing where the spinlock is held, you will have to rearchitect things a bit.