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_PASS autolearn=ham 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 6E4EBC43381 for ; Mon, 18 Feb 2019 12:10:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45918218AD for ; Mon, 18 Feb 2019 12:10:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730741AbfBRMKU (ORCPT ); Mon, 18 Feb 2019 07:10:20 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:59270 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730631AbfBRMKU (ORCPT ); Mon, 18 Feb 2019 07:10:20 -0500 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 5F67B3F4A3668C11CFFE for ; Mon, 18 Feb 2019 20:10:17 +0800 (CST) Received: from [127.0.0.1] (10.57.71.8) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.408.0; Mon, 18 Feb 2019 20:10:09 +0800 Subject: Re: possible deadlock in console_unlock To: Sergey Senozhatsky CC: Sergey Senozhatsky , , References: <20190216072127.GA1945@tigerII.localdomain> <20190216073856.GA9979@tigerII.localdomain> <71b097a7-03c5-8a65-76fa-24312b452b51@huawei.com> <20190218054649.GA26686@jagdpanzerIV> From: Yao HongBo Message-ID: Date: Mon, 18 Feb 2019 20:09:41 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <20190218054649.GA26686@jagdpanzerIV> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.57.71.8] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/18/2019 1:46 PM, Sergey Senozhatsky wrote: > Hi, > > On (02/16/19 15:59), Yao HongBo wrote: >>> GFP_NOWARN is probably the best option for now. Yes, it, maybe, >>> will not work for fault-injection cases; but printk_safe approach >>> is harder to push for, especially given that printk_safe maybe will >>> not even exist in the future. >> >> I have tried GFP_NOWARN, but the problem still exists. >> Only print_safe contexts for tty locks can solve the problem. >> My test scenario is falt-injection. > > Oh, I see. Yes, fault-injection is special. > > I suspect that this patch series can be helpful then > https://lore.kernel.org/lkml/20181016050428.17966-1-sergey.senozhatsky@gmail.com/T/#u ok, i'll try it. Thanks. > but first we need to figure out if printk_safe will > stay in the kernel (this will take some time). > > -ss > >