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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 D9DE8C4360C for ; Tue, 8 Oct 2019 19:17:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB6B7206C0 for ; Tue, 8 Oct 2019 19:17:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570562253; bh=17f9i3oR5PbDQJgABtFQNuHXK2qtBHl7SdFLyVRsNd4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=XXmahsf7Uw/+oNvVQn30t+VoMQnL8Whi1IR6oCC2ii/Tbd81aOhEKncFfb29AwOi1 E/RDMvMORyEHAaNV5nTfssbB162Ic1bvJBc1qEWONPDirVOoRgVga+c/Giey9VMlUc pJaMYWsq9gjbS9Jm/HIVx7XGc7raYTIbE6vBjHjk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729802AbfJHTRc (ORCPT ); Tue, 8 Oct 2019 15:17:32 -0400 Received: from mx2.suse.de ([195.135.220.15]:34248 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726439AbfJHTRc (ORCPT ); Tue, 8 Oct 2019 15:17:32 -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 7F338B112; Tue, 8 Oct 2019 19:17:30 +0000 (UTC) Date: Tue, 8 Oct 2019 21:17:28 +0200 From: Michal Hocko To: Qian Cai Cc: Christian Borntraeger , Petr Mladek , Peter Oberparleiter , akpm@linux-foundation.org, sergey.senozhatsky.work@gmail.com, rostedt@goodmis.org, peterz@infradead.org, linux-mm@kvack.org, john.ogness@linutronix.de, david@redhat.com, linux-kernel@vger.kernel.org, Heiko Carstens , Vasily Gorbik Subject: Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk() Message-ID: <20191008191728.GS6681@dhcp22.suse.cz> References: <1570228005-24979-1-git-send-email-cai@lca.pw> <20191007143002.l37bt2lzqtnqjqxu@pathway.suse.cz> <20191007144937.GO2381@dhcp22.suse.cz> <20191008074357.f33f6pbs4cw5majk@pathway.suse.cz> <20191008082752.GB6681@dhcp22.suse.cz> <1570550917.5576.303.camel@lca.pw> <20191008183525.GQ6681@dhcp22.suse.cz> <1570561573.5576.307.camel@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1570561573.5576.307.camel@lca.pw> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 08-10-19 15:06:13, Qian Cai wrote: > On Tue, 2019-10-08 at 20:35 +0200, Michal Hocko wrote: [...] > > I fully agree that this class of lockdep splats are annoying especially > > when they make the lockdep unusable but please discuss this with lockdep > > maintainers and try to find some solution rather than go and try to > > workaround the problem all over the place. If there are places that > > would result in a cleaner code then go for it but please do not make the > > code worse just because of a non existent problem flagged by a false > > positive. > > It makes me wonder what make you think it is a false positive for sure. Because this is an early init code? Because if it were a real deadlock then your system wouldn't boot to get run with the real userspace (remember there is zone->lock spinlock involved and that means that you would hit hard lock after few seconds - but I feel I am repeating myself). -- Michal Hocko SUSE Labs